The Cumbrous line of feats have to be some of the most WHY WOULD YOU USE THESE feats I've read in a while.
Cumbrous Fortitude: Give yourself a +6 bonus to one Fortitude save, be Staggered for the rest of the encounter!
Cumbrous Reflexes: Give yourself a +6 bonus to one Reflex save, be Prone and Dazed! Of note is that no duration is given for the Daze caused by the feat, so your Dazed forever if you use it once (I think the intent was one round.)
Cumbrous Will: Give yourself a +6 bonus to one Will save, be Shaken for the rest of the encounter! Not that shitty, comparatively, but the Shaken caused by the feat stacks with itself.
Cumbrous Dodge... ...is actually semi-useful: +2 untyped bonus to AC for the remainder of the encounter, you're Fatigued at the end of it. Might be something nice to pick up (if only because untyped) if you're immune to Fatigue.
Improved Web, also from Savage Species, is an interesting feat for anyone who has the ability to use Webs as an Extraordinary ability; namely, you can full-attack with them, attacking a number of creatures equal to your Dexterity modifier. The only limit is that they have to be within 10' of each-other.