While the move or ability doesn't have to be competitively viable, it'd be nice if they did something, or something more than what they already do.

Splash > Lowers the opponents accuracy?
Slow Start > Effects start at the start of the battle, not the time it's actually been out (stall for 5 turns and then sweep?)
Teleport > Acts like a fusion between baton pass and fly, without passing stats
Illuminate> Lowers opponents accuracy a bit OR ignores evasion boosts

What do you guys have?