Why did I make this? Frankly I'm not sure.
D20 Modern casters have five important distinctions from a D&D caster.
1: Limited Caster Level: Since all casting classes are Advanced Classes, they require three or more levels in a basic class to enter. This means your CL will be 3+ levels behind all enemies. The result of this is that direct damage is even worse than D&D (but see 4), saving throws will be harder and buffs are about the same potency with slightly less duration.
2: Defense Bonus: All d20 Modern classes automatically grant a bonus to armor class, which applies to touch AC. This makes touch attacks rather inaccurate against enemies that advance by class level.
3: The Masquerade: By default d20 Modern assumes that “normal” people will attribute mundane explanations for magical effects and appearances. This makes magic a good deal more subtle than using mundane options, which is nice if the campaign doesn’t want big incidents on the news. You also don’t have to carry around any obvious weapons to function and most mundane security will quickly fall to magic tricks. On the other hand, those who aren’t “normal” will instantly realize you aren’t normal if you have any obvious effects up.
4: Low Massive Damage threshold: A character’s massive damage threshold is only their con score. Damage exceeding this forces a save or negative HP. This damage is relatively easy to hit, but the DC doesn’t scale. By the time you can hit the treshold consistently (before saves for half) enemy saves aren’t that threatened by a DC15.
5: Harder to sink enemy saves: Few spells cause conditions that lower saves, and there’s few mundane ways to do it. The only reliable ones are Prayer (-1), Bestow Curse (-4, requires touch) and the Frightful Presence feat (-2)
There are only five (technically six) sources for spells in d20 Modern: Core, Urban Arcana, Menace Manual, d20 Past and Dark Matter (also the web article Even More Modern, but everything in that is a less finished version of Urban Arcana spells). Of these, the first three are OGL, the third has one crappy spell, and the fourth only has Shaman exclusive spells.
Mage/Techno Mage/Sorcerer list:
Arcane Graffiti N/A: Its long lasting duration makes this a downtime spell, largely fluff based. The ability to embroider your gear is neat.
Dancing Lights **: It’s like Light with a few differences. Better if you have a tall building to stand on, worse if you’re relying on some kind of launcher (like a sling). Note that Urban Arcana's table lists this as a level 1 spell instead of the level 0 it is in core/srd. In that case, it deserves ZERO stars.
Daze ***/*: This cantrip is less useful than its D&D counterpart because you get it three levels late when it starts to become less useful. Still usable for distracting mundanes I guess, and temporarily useful if you got it via feat.
Detect Magical Aura N/A: Depends greatly on the DM to be useful, but when it is it’s mandatory.
Haywire *****: A distraction and a way to bypass security. Note that the spell never actually says electronic device (though it seems to have been intended to do so), so it can work on mechanical devices.
Light **: Non-combustible, long lasting, light is cheap in this setting, even if you want it hands free. The sole saving grace is using it as a signal at night if you can stick it on an object and launch it (like with a sling). An extra star or two in a d20 Past campaign.
Mage Hand ****: Useful to bypass some security. Let down by the requirement line of effect be a straight line.
Magic ID **: Could be very useful when you need it, but defeated by the short duration combined with components and inability to let someone see it.
Mending *****: Just casting this once per day via Magical Heritage alone is enough to beat a specialist at their own game.
Message ***: Largely replicated by common technology that’s easily concealed, but enough areas prohibit that it can be useful. Also a good deal more secure and can’t be jammed.
Prestidigitation ******: Still as good as it normally is, but also good for destroying pesky evidence.
Read Magic N/A: When you need it, you need it. When you don’t, you don’t.
Resistance **: A bit better than normal since cloaks of resistance aren’t everywhere, but the 1 minute (not even 1 minute per level) duration hoses it.
Spells as Powers
Burst *: Too small a lead, even as a free action.
Distract : A -1 penalty after you activate it on a target? Can I rate this zero stars?
Far Punch : 1 damage? Even as a once a turn free action infinite use this wouldn’t be too useful. Zero stars again.
Finger of Fire : Did d20 modern writers hate Psionics? It came out before 3.5 Psionics so the answer is likely “Yes”.
Alter Data (DM) ***: Variant of degauss.
Blood Weapon (DM) **: This would be much better if it didn’t last for one attack. As is, the ability to trade 5 damage for ~6 on a target isn’t great. Better (***) if it works with splash weapons.
Burning Hands *: The range is too short and the damage too low for a world where everyone has guns. Junk. Gets the star only for arson purposes.
Fear **: Save or Lose, but HD limits hurt this a lot. Good for removing normals I guess.
Change Self ****: Quick change alone is good, but it’s good for augmenting a disguise. Also helps hide all your weird stuff.
Clean *****: How did this spell not get into D&D? Evidence clearing alone makes them great, but it has other uses.
Comprehend Languages N/A: Plot device spell. Duration is too short for Japanese video games.
Degauss ***: More evidence destruction.
Feather Fall */*****: Unlike D&D, where you’ll encounter pit traps and other unexpected falls, this spell will only be useful if you’re around tall buildings or airplanes. If you’re going to do either of those, this should be prepared, if only to enable a cunning escape.
Hold Portal ***: Impeding pursuers is more likely to be useful in a d20 Modern game than normal D&D. Can shut down all kinds of technology or create a distraction. Verbal only.
Instant Identify N/A: If you get un-IDed magic items you need this. If you don’t, you don’t.
Jump *: +30 to Jump sounds nice until you realize how little an increase that actually gives you and that you cap out at 8 feet high anyways.
Mage Armor *****: Congrats! You actually have better armor than most d20 Modern characters now! Allies too!
Magic Missile **/***: Benefits from the Masquerade and not being detectable, but also hurt a lot by the late entry. If your GM reads the increase to come from character level instead of caster level (or you somehow got them to approve Practiced Spellcaster), give it the full three stars.
Magic Weapon ****: Solid buff to an ally, especially given how hard it is to increase gun damage and rarity of magic weapons. If you entered (Techno) Mage via Smart Hero with Exploit Weakness you can actually use it pretty decently.
Mask Metal */***: Good to bypass a common security device. A few minor things sink this though: The material component is itself visible to metal detectors, more modern scanning devices won’t be impacted by this spell and the “single object” means you need a separate casting for every piece of ammo and the magazine. If your DM ignores these, give it the full three stars.
Obscuring Mist *****: Another spell that’s even better in d20 Modern due to the presence of high speed vehicles. Aside from its combat utility, you can cause all kinds of problems with this, especially in a chase.
Power Device ***: Vague on what its max size is. ***** in a sci-fi campaign with limited ammo energy weapons if it can apply to them.
Ray of Fatigue **: No saving throw, but a short range and fatigue isn’t nearly as debilitating for ranged combatants as it is for melee ones (who can’t charge).
Shield ***: The short duration and personal only make it not as good as mage armor, but they stack.
Sleep **: HD dependent and late entry don’t mix. 2 stars for the ability to disable mundane witnesses.
Summon Vivilor I **: Summoned creatures are considered weak for the level you get them in normal D&D, depending on SLAs and expendability to maintain relevance. Delay being able to summon them by 3 levels, give them no SLAs and exclude Augment Summoning and the only reason I give them two stars is the ability to be a distraction/alarm bait.
Trace Purge ***: More evidence removal, but got enough omissions to make it clear something happened.
True Strike ****: A useful buff as always. Does not actually help sniping that much, since it will only compensate for about 200 yards of distance with a scoped rifle.
Powers as Spells:
Charm Person *****: Psionic cantrips may have sucked, but this is great. The ability to just make someone a friend with a gesture and words opens up all kinds of doors in the modern world.
Control Object ***: Use this as a greater mage hand rather than an attack power.
Lesser Concussion *: And we’re back to suck. It doesn’t even scale, which is just sad.
Lesser Mindlink ****: The silent part is what makes this better than message or a cell.
Arcane Lock N/A: Worth casting on your car or base, but the component DC is just barely too high to make it castable all the time.
Blur ***: Good defense boost.
Burglar’s Buddy ****: Good, broad spectrum survaliance defeating. Only shame is the low duration.
Curse of the Putrid Husk (DM) ****: An outright save or die as a second level spell?! This has none of the restrictions (long casting time, bad range) of spells like Sleep, Hold Person, or (in normal Dnd) Color Spray.
Darkvision ***: This can be accomplished with tech, but it’s expensive and cumbersome.
Dataread **: Doesn’t really do anything common tech can’t, but has some niche uses if you can’t take the original with you. Whoever wrote this doesn’t know how a bar code works.
Enhance Ability ****: Broadly useful buff of +2/+3 to things based on one ability score. The ability the choose when casting makes it better than the traditional Animal’s Attribute series, as does the lack of items to do this.
Glitterdust *****: It’s glitterdust, and not the nerfed PF version either.
Invisibility ****: A good defense buff (if you’re just buffing allies it won’t break the spell) and utility power.
Knock ****: Useful anti-lock spell. Lots of locks in the modern world.
Levitate **: The commoness of ranged attacks make this a poor choice for combat, but still useful for infiltration. Spider-Climb is generally better.
Locate Object ****: Some nice divination that can sidestep an investigation if used right (Note, Core and Urban Arcana’s table gives this as a 2nd level Arcane spell, but the text does not give it as a mage spell at all)
Machine Invisibility **: Invisibility does most of this, but has a small niche in that it blocks other forms of detection by machines.
Magic Message ***: Interesting when used on a publicly visible device, which the spell specifically allows.
Protection from Arrows/Bullets **: The DR will go quickly when a basic 9mm does 2d6, and the nerfed duration stopped it from being an all-day buff.
Relay Text **: Niche use for private communication. Note the range is unlimited, unlike Magic Message.
Resist Energy ***: Typically only protects against monsters, but when you need it, you need it.
See Invisibility N/A: Entirely dependent upon if you actually fight invisible creatures, which is not guaranteed in d20 Modern. Good for a scroll I guess.
Spider Climb ***: Largely used for getting into places you’re not supposed to be able to.
Summon Vivilor **: Gets two stars for flight utility. Still useless in combat.
Web ****: How does this work with vehicles? Never the less a good buff.
Wings of Icarus (Dark Matter) ***: Has largely the same utility as Spider Climb. The lack of a proper Fly spell means this actually could benefit from an Extend metamagic.
Zap (Dark Matter) **: This would be a nice spell in D&D, but your being behind in CL and prone being a good thing for a gun users hurt this.
Brain Lock ****: Strictly better Hideous Laughter (which isn’t even in this system).
Clairaudience/Clairvoyance *****: Espionage and the girl’s locker room.
Claws of the Bear *: You’re not a melee combatant.
Electric Charge : 2d6 on a touch attack? Strictly worse than the two under it. Zero stars.
Concussion *: One use 3d6 damage that doesn’t improve is terrible.
Inflict Pain *: Strictly better than Concussion because you can concentrate on it and use it for multiple rounds. You still have to concentrate on it and it’s still lame.
Breath of the Deep (Dark Matter) ****: Save or die. I’d rather use Hold Person on a humanoid, but against anything else...
Dispel Magic N/A: Really campaign dependent. Generally though your opponents will have higher CL than you do.
Displacement ****: A solid defensive buff.
Effigy of Black Binding (Dark Matter) */****: The need to prep the component renders this rather useless. If you have Eschew Material Components, it’s a fine way to prevent an enemy from hurting you.
Electromagnetic Pulse ****: You can cause a good deal of havoc and shut down a lot of stuff in addition to stopping a lot of surveillance and devices being used against you.
Fireball ***/****: Direct damage gimped by your lower caster level, but over a good area. For Sorcerer however, Fire Focus and Frightful Presence give this a good chance to instant kill foes through massive damage.
Flaming Projectiles **: I always thought this spell would have been perfectly fine as a level 2, maybe even level 1, spell if it applied to a weapon or 50 projectiles in D&D. I still think so in d20 Modern.
Gaseous Form ***: Solid for escape or infiltration.
Greater Magic Weapon ****: Good all-day buff. Sadly doesn’t scale to Archmage level CL, but +3 weapons are rare in d20 Modern anyways.
Halt Undead ****: Great if you fight undead. Otherwise useless.
Haste ****: Notice how WotC realized 3.0 Haste was broken before 3.5 came out? Still a solid buff if you have party members who can attack.
Hold Person ****: Save or die. Was better a level ago for Acolyte, but still nice. Unlike Haste, this does not have the 3.5 nerf of the target getting a new save each round. Do note that you still can’t CDG in d20 Modern with a ranged weapon, even at point blank.
Improved Arcane Lock: Wait, this only lasts a few hours, but still needs an expensive component? Zero stars.
Invisibility Sphere ****: It’s invisibility for the whole party, so long as they don’t stray from you.
Keen Edge ****: Another 3.5 change not reflected in d20 Modern is that you can stack critical range increases.
Lightning Bolt **: It’s direct damage, but not even in a good area.
Nondetection ****: Stop diviners. Thanks to the way d20 Modern’s wealth works, the material component is effectively free.
Phantom Chopper **/***: This spell sounds nice, but “realistic looking” does not mean “in the database” and will instantly be identified as a fake. If you’re away from government roads (or better yet, roads at all) this is nicer, but only works for you.
Secret Pocket ****: Bag of holding, but very limited size. Still, this makes it easy to smuggle things past security. A rifle is about 7 inches at the widest point unloaded/flush magazine, and closer to a foot if it has an optic, so you’d need something a bit bigger than cargo pants pocket.
Shutdown ***: More anti-security stuff, but less destructive. Also centered on a point so it is less effective against vehicles.
Slow ****: Still great debuff.
Summon Vivilor III **: Terrible at combat and no new utility, but if you can last the full round action you might throw 1d4+1 weaklings that the enemy must waste attacks killing or be hit with aid another.
Tongues N/A: Plot device power.
Vampric Touch *: Melee touch attack and gimped by your low caster level. A whole 5 temporary HP on average when you first get this!
Wall Walk ***: Trying to fight on the wall is unlikely to be a good idea when everyone is a ranged attacker, but still has its uses.
Water Breathing N/A: Another spell that’s mandatory or useless.
Detect Thoughts ****: The deck of cards may be weird and you get this a level later than Telepath, but good information to have. Remember how normal people don’t realize magic is happening?
False Sensory Input ????: I have no idea how this power can be used beyond making people look like someone else (which is accomplished with lower level spells). I’m likely missing something.
Mental Blast ****: Stun is a good effect and this has a duration that is, on average, better than rounds per level (and still long enough to CDG on minimum rolls).
Mind Darts *: 5d6 fixed against a single target? 3rd level? Save allowed?
Mindlink **: I’d rather just use three castings on Mindlink than spend one 3rd level slot. Really needs something more.
Suggestion *****: Any form of mind control is great in a world where most people have no idea it exists and low will save saps hold some power, even if you do get it late.
Animate Dead ?: Finally! An effective minion spell! Sadly actually keeping that giant skeleton is going to be a problem in the modern world depending on how mundanes see it. Plus getting your hands on a large+ creature that flew by magic and is suitable as a mount will be annoying.
Arcane Eye ****: Less useful for spying, but more useful for checking ahead of you.
Banish (Dark Matter) *****: Save or die against any non-native shadow creatures. This breaks Urban Arcana as a setting.
Bestow Curse ***: A good way to hose saves or shut opponents down, but getting to melee is harzardous.
Blood to Acid (Dark matter) *: This is Heat Metal, but worse and two levels higher.
Clown Car ?: Interesting. Requires you have a need to transport that many people though.
Confusion *****: Mass save or lose with a good chance of making your enemies kill eachother.
Detect Scrying ?: Useful if the GM actually pulls that on you. Nice duration.
Dimension Door *****: It’s teleportation. Your cargo capacity will be a tad limited though.
Energy Trap: The damage would have been bad 6 levels ago. Zero stars.
Fear ****: Mass save or die.
Gris-Gris (Dark Matter) *: A variant Spell Resistance, and even worse. Remember that in d20 Modern casters are either dragons, operate under the same rules you do or are so high a caster level this minimal SR means nothing to them.
Ice Storm *: This is direct damage suitable for last level with a very lame rider. Would have been a two star last level.
Magic Bullet **: Gives 50 rounds of ammo a low save rider. The duration is long enough I suppose you’ll get at least two enemies to roll a 1 on Panic Bullet, but its unreliable. This is ***** for acolyte who get 300-650 points of healing.
Minor Globe of Invulnerability **: Few virtually no creatures uses spells offensively in d20 Modern. This will however stop a good deal of the shenanigans Baal is able to pull.
Phantasmal Killer *: You’ve got much better save or die this level than one that requires 2 saves.
Scrying ****: Shortcuts a lot of plots and good for info gathering.
Shout **: You get a lot better save or dies this level, but this is the only fortitude flavored one.
Stoneskin *: Remember Protection From Arrows? Well this is it but against melee attacks too for the price of a new motorcycle.
Summon Vivilor IV: Nothing new from 3, and even worse for its level. Unless you want to do the aid another trick on a flyer, there’s nothing worth using it for.
Wall of Fire *: This spell did bad damage for its level in D&D and its worse here.
Wall of Ice **: The wall will break if anything level appropriate attacks it, but that still costs them an action. Has a bit of utility.
Via Negativa *: You’re not grappling anything and you’ve got better ways to kill someone willing to shake your hand.
Wire Walk *****: Has some differences between this and Dimension Door. Both are good.
Forced Mindlink: Am I missing something? This power would have been useless as a first level one.
Lesser Domination *****: See Suggestion. I’m not sure why Dominate Person but Better is two levels lower level in d20 Modern than D&D, but I’ll take it.
Natural Armor *: Too little duration
Tailor Memory ????: I’ve got no idea how to use this. Sadly inferior to Modify Memory so you can’t delete memories of mind control.
Cloudkill *: Doesn’t do anything to creatures with level appropriate HD, unlike the 3.5 version.
Cone of Cold *: Is this a third level spell?
Dreamwalk (Dark Matter) ****: Arcane Eye but not stopped by barriers
Hold Monster ****: Not as good for the level as Hold Person was, but still good and still the 3E version
Instant Connectivity ****: Wire Walk, but more people. Also: Holy shit that’s an expensive hard drive for the focus!
Passwall *: Only works through wood, plaster and stone. Did you know modern concrete has steel reinforcements in it? You can Dimension Door past anything lower security.
Phantom Limousine **: Not street legal.
Phantom Projectiles **: OK buff but too late.
Phantom Watchdog **: Late Spiritual Weapon with some alarm utility.
Secret Vault ***: Good smuggling/securing stuff. Just how small the replica is changes this spell a lot.
Seeming *: Shouldn’t this be a level 2 or 3 spell?
Summon Invisible Stalker (Dark Matter): This has at least a 1 in 20 chance each hour of backfiring and trying to kill you?
Summon Vivilor V: See IV.
Synchronicity ?: No strict mechanical effect but a bonus against AoOs but interesting RP considerations.
Telekinesis **/***: Your caster level is too low for consistently picking people up. Once you hit Archmage levels however it can take people out of the fight.
Wall of Force ****: Stops attack.
Wall of Iron **: Too expensive.
Wall of Stone ****: Stops attacks, but in a world of a building codes and concrete the building utility isn’t there.
Domination: This would be great… if lesser domination didn’t exist. It does though and the improvement from the lesser version is so minimal I won't bother rating this.
Mind probe ****: Information gathering, and a fort save for some reason.