>>35228231Any immediate offensive stat boosting is top tier. The best ones of this category are Pure/Huge Power, and Speed Boost. Beast Boost, Moxie and Soul Heart are also very good but not immediate. Defensive stat boosting is not as powerful but also good.
For defensive abilities, Wonder Guard is certainly the best. Magic Guard and Regenerator are both incredibly strong as well. Disguise and Sturdy are also good options. Depending on your typing, type immunities can be a boon defensively. Last but not least, Imtimidate is highly useful on any mon.
As for other abilities,trapping ones like Shadow Tag/Arena Trap/Magnet Pull is probably the actual best ability in the game, because it can 100% secure knockouts with a good matchup, which is something no other ability can do. Prankster can be invaluable for a support, while automatic weather and terrain setters can be invaluable to an entire team strategy.
Passive BP boosters like tough claws, sheer force, -ate abilities, etc are quite good and almost always useful. Also, protean deserves special mention for doing wonders offensively (stab on everything) and defensively (think kecleon shenanigans with sucker punch to dodge psychic, than sneak to dodge fight)
