Vivillon, aka How to Fix Everything Wrong with Mothim. It's definitely predictable, usually running just one set, but that set is pretty good among lower-tier contenders. As said set has already been posted, I'll give a few OO's for it:
-Energy Ball can replace Bug Buzz depending on what threatens you more, since it hits Rock-types (plus Ground-types with Rock coverage) a little better, although it does sacrifice some power.
-HP Ground is sort of an option, but should only be considered if you have a teammate who needs to induce sleep more than Vivillon, or are okay with the loss of power from Bug Buzz or Energy Ball.
-If you think you can get Vivillon in for free against something it naturally outspeeds, you could try another item like Life Orb.
The risk I took was calculated, but man, am I bad at math.