FeatsEmpower Spell (Core): noted because per PBH the entire range is Empowered (ie 1d6+15 is 16~21+50%).
Fiery Spell (Sand): any spell with the fire descriptor deals +1 damage per die.
Pyro(S&S): spells that light stuff on fire +1 damage per die
Reserves of Strength (DL): +3 to caster level and break cl caps, like wiz 9 can use this to shoot 12d6 fireballs.
SpellsAcid Sheath (SpC): any spell with the acid descriptor deals +1 damage per die.
Caustic Mire (CM): if an effect deals fire damage it does +1 damage per die.
Raging Flame (SpC): fire damage -only- is done with +1 damage per die.
Assay Spell Resistance (SpC): +10 to spell resistance check on the next spell cast.
Spell Enhancer (SpC): +2 to caster level on the next spell cast.
Sonorous Hum (SpC): removes the need to concentrate on the next spell cast.
ItemsRing of Mystic Fire (MiC): 3 charges/day, +[2/3/4]d6 to any fire spell. *Several variants of this exist*
Feats - [Cold]Snowcast (FB): adds the [Cold] descriptor to all spells you cast if you have snow.
Frozen Magic (FB): up +2 to caster level with all cold spells if it's cold outside.
Cold Spell Specialization (FB): up to +2 damage per die with all cold spells if it's cold outside.
Draconic Aura (DM): up to +4 to the save DC of any elemental spell type chosen (scales by level).
Draconic Power (CAr): +1 to the save DC of any elemental spell type chosen you cast.
Cold Focus (FB): +1 to the save DC of any cold spell you cast, stacks with all the other focuses.
Greater Cold Focus (FB): +1 to the save DC of any cold spell you cast, stacks with all the other focuses.
Items - ColdIcemail Armor (
Online): +2 to the save DC of cold spells you cast.
Spells - ColdCold Snap (FB): lowers the temperature by up to 50 degrees, +1 damage per die with cold spells.
Control Temperature (FB): reduce or raise the temperature by one temperature band per five caster levels.
Other - ClassesWarmage (prc, DL:AoM): +3 damage per die.
Stormcaster (SW): +1 sonic damage per spell level if the spell deals electricity damage and adds a save vs stun.
Examples of useWarmage/Stormcaster casts a Snowcast + Energy Admixture(electricity) + (Energy Substitution(acid) + (Blistering Spell + Fireball)) under Cold Snap, Caustic Mire, and Cold Spell Specialization. The spell has the [Acid, Cold, Electricity] descriptor, deals electricity & acid damage plus 2 fire damage per spell level. Via Reserves of Strength @cl21 the Fireball deals 23d6+161 electricity, 23d6+161 acid, +3 sonic, +6 fire, and stuns. 494 avg, 733.5 empowered.
Warmage casts Persisted Acid Sheath & Persist + Energy Admixture(acid) + Fiery Spell + Fire Shield using a Mystic Ring of Fire. The spell has the [Acid, Fire] descriptor and deals fire & acid damage. @CL15 Attackers take 5d6+40 fire, 5d6+40 acid, and 30 acid damage. 145 avg, 202.5 empowered.
Holy Fire Shield is like Fire Shield but is a spell level higher, it has some BoED fluff but as a separate Spell you can tack on it's Fire-Shield-ness for even more damage. And if you *really* wanted to go down this road. Radiant Shield & Cacophonic Shield can be used as well. Deal 800ish damage each and everyone time someone hits you. Who needs Roiler's Gambit?