Psion
Adventurer
- Class Variants (on a case-by-case basis. This is really a more formalized version of what was already was mentioned in the DMG.)
- Specialist Wizard Variants (these are cool)
- Complex skill checks (been doing this informally already)
- Weapon Group Feats (it's about time...)
- I am using Second World Sourcebook's version of Class Defense Bonus, and consider the UA version sloppy by way of comparison.
- Action Points (already using in my Second World game, which uses d20 modern and D&D rules, but these are a nice refinement.)
- Metamagic components (again, am already using a version of this from another source, in this case Plot & Poison.)
- Spontaneous Metamagic (this should have been part of 3.5 AFAIAC. Most players won't touch metamagic IME.)
- Legendary Weapons (again, already using; this came from TGM.)
- Contacts (though I may opt for something more freeform... I'm not convinced I need to abide by a level schedule.)
- Taint (again already using, the version from OA.)
- Insanity (I always thought that using a shortcut of the confusion spell was lame. But again, this is something that other publishers have already done.)
A lot of stuff is really not on the list of stuff that I think is all that helpful or I have seen better (IMO) versions of in other publishers stuff or my own house rules.