There are some fun finds in the Ravenloft material.
From Van Richten's Arsenal:
The viper bite weapon mod allows administration of a liquid with a hit. Specifically, if you beat an opponent's touch AC then the liquid splashes out on the target and on all adjacent squares. This occurs even if you wouldn't actually hit your target with your attack. If you beat their full AC it only affects the target. It specifically states that you can load any kind of liquid into the weapon, but when you hit it's treated as if you had hit them with a flask of the liquid, which somewhat limits it's usefulness.
The spell insight grants a +10 insight bonus to spot and search checks for 1 round/level. It's a second level spell.
The spell awaken guilt is a third level spell that renders the target flat footed and unable to take any actions at all for 1d6 minutes. It's touch range, and mind affecting, and can also change your alignment to the opposite of what it was? But this is left up to the DM.
The deconstruct spell lowers a construct's DR by ten points.
The diminish undead spell lowers an undead's turn resistance by 3.
The eternal slumber spell, among other things, removes a lich from it's body.
The shackle spell paralyses (sort of) a creature with no save. 3rd level spell.
The epiphany spell allows another saving throw against an evil spell or profane effect. I have no idea what constitutes a "profane effect."
The binding weapon enhancement is a +3 weapon ability that can be applied to a slashing or piercing metal weapon. It turns non-elemental/fey/outsider/incorporeal creatures into ghosts when you kill them with the weapon.
The heartseeker weapon enhancement is a +5 weapon ability that instantly kills the target on a critical hit. It has a short and vague list of immune creatures, and outsiders get a fortitude save, but everyone else is insta dead.
The ivory amulet of the beast gives you the lycanthrope template while worn.
A ring of reversion will return anything to it's original body with no save. The body must be within 50 miles.
A soul searcher medallion gives true seeing, as well as revealing the true alignment, active curses, illusions, shape shifting, magical dweomers, and so forth? (Whatever that means).
A bed of meditation can give an "effective" +10 bonus to intelligence and wisdom for one hour per use.
A censor of warding prevents undead with SR less than 16 from entering a structure. Why? No idea.
The Medallion of Set gives any character a dread familiar. It's like a familiar, but way too loyal.
Catalytic Poison alters a poison to affect only one creature.
Corporeal Purgative can transfer all diseases from one target to another.
Spiritual Purgative does the same, but with curses.
Essential Cogulant stores the soul of a dying or recently dead creature and allows it to be placed into another body.
A philosophical child is a nearly exact copy of any creature that you take a tissue sample from. Under your control entirely. Forever. Broken broken broken.
Enlightened child is the same thing, but gives three bonus abilities off of a list that includes immortality, the ability to liquefy itself, and EX alter self at will.
The portents feat grants a free augury once per day. The only requirement is a 15+ wisdom score.
The pistoleer prestige class grants the ability to shoot around cover with gunpowder weapons.
From Van Richten's guide to the walking dead:
The composite walking dead template allows combining some abilities from a couple of creatures onto another.
It has a ritual section that states if an hour long ritual (with apparently no cost) is conducted before casting animate dead, then the undead gains 1d4+1 intelligence and +1 turn resistance. This intelligence increases by 2 per century the undead lives, to a maximum of +6 from three centuries.
The reign undead skill allows you to make a check to control uncontrolled mindless undead.
The bind undead feats allow you to spend Xp to permanently bind undead to your will, while removing them from your animation and/or control pool.
The bind salience feat to permanently add salient abilities to undead. Some of the salient abilities are pretty wild. For instance, leaping grants an unnamed +30 bonus to jump checks, and doubles jumping distance. Deathless warrior grants nigh immunity to damage. Other near abilities include spawn creation and telepathy. Someone could honestly write an entire handbook just on salient abilities.
From champions of darkness:
The manipulator prestige class grants a funny bardic music ability based off of diplomacy. And you gain it all at first level.
The mesmerist prestige class has the ability to lower will saves against their hypnotisms. This effect apparently lasts forever and stacks.
The energy drain feat allows you to spend a turn attempt to drain a number of levels or hit dice equal to you charisma modifier. This can be used after you succeed on any melee touch attack.
The ethereal touch feat lets you touch and harm incorporeal creatures. It also has an odd clause about allowing the character to possess the corrupting touch ability of a ghost, but it doesn't grant it. So I guess it's nice if you were prohibited from having that ability for some reason.
There is another version of the extra domain feat.
The feral rearing feat gives you the animal type instead of whatever type you had before. I'm sure this opens up tons of cheese. At the very least, it allows you to be a target for awaken animal. It also gives some other benefits and makes you illiterate.
The hollow feat makes you soulless, which, among other things, makes you immune to energy drain, magic jar, trap the soul, malevolence, and all other forms of possession.
The life force sacrificing feat allows you to damage yourself in order to swap out your prepared spells for any other spell that you could prepare. The damage is small, but it can't be healed by magical means.
From heroes of light:
The kiss of dawn feat refreshes all of your spells every day at dawn. Apparently regardless of if you rested or not.
The wealth feat gives you gold each month. The amount is entirely insignificant, but it's sort of unique that it's a feat that gives you a steady income for doing nothing.
From player's guide to ravenloft:
The ghostsight feat grants permanent see ethereal, but without the invisibility piercing part.
The curse rules are nasty. They can be used by any character, but require a charisma check to take effect. The save doc can get really high, and it doesn't require line of sight or line of effect. It seems like it has infinite range. Also, as an amusing side note, it doesn't seem to say what sort of save the target gets. Out of the book curses include -8 to an ability score, instant death, permanent transformation into a monster (could be a blessing), and lycanthropy.
Whew. This was a much longer post than I intended. I just kept running into more things. I'm sure I missed a bunch, but I will post them as I find them.
