Talo! said:
A addition to a current ability.
Run away: A pokemon with this ability is allowed to switch even under the effect of arena trap, magnet pull and mean look.
This would be an interesting ability for an anti-Wobbuffett pokemon.
Back on topic -- I thought up a few abilities that I liked. Here are a few.
Desperate Strike: When the pokemon's Hit points have entered the red, all moves it has are 100% accuracy.
----explanation-- Tack this on a pokemon that learns a OHKO move. The pokemon still loses to extremespeed/quick attackers and faster pokemon. But, it's still viable.
Healthy Eater (For Munchlax/new Snorlax ability): Gain 2x health from Leftovers and similar items (Oran berry etc).
Incorporeal: Not hit by physical contact moves (is there one already like this?)
Steam Bath: When struck with water attacks, 20% chance of burning opponent.
Sub-zero: Water attacks gain 5-10% chance of freezing (whichever is more balanced).
Flan the Flames: Flying type moves gain 10% burn chance (flying/fire types).