Mainly ones that can hinder great Pokemon
Slakings-can not Atk on consecutive turns
Regigigas-Atk and speed are halfed for five turns
These two Pokemon have amazing stats - without the abilitys would both probably be über
Are there anymore such as archeops with halfs def when under half hp I think
Also apparat from skill swap which are good ways to counter the abilitys
Well Defeatist, Slow-start, and Truant are the ones with negative side effects. Honey-gather, Illuminate, Pickup, and Runaway have no effect in competitive. Rivalry, Klutz, Weak-Armour, Big-Pecks, Stall, and Keen-eye rarely have any use though some can be used strategically.