Feats in the SRD that are actually worth taking (in an appropriate build), omitting useless prerequisites:
Augment Summoning, Combat Reflexes, Craft Magic Arms & Armor, Craft Staff, Craft Wondrous Item, Extend Spell, Improved Familiar, Improved Initiative, Improved Precise Shot, Improved Trip, Improved Two-Weapon Fighting, Leadership, Natural Spell, Power Attack, Precise Shot, Quicken Spell, Rapid Shot, Scribe Scroll, Spell Focus, Spring Attack, Two-Weapon Fighting, Weapon Finesse.
That's a total of 22 feats, out of a total of 110, or exactly 20%. Sad. Even if you add in prerequisites, you're only upping the total by 4.
Still, the other stuff like Negotiator and Toughness are options on the table. Not worthwhile options in an even halfway optimized game, but your game may not be one of those.