>>34403751It's just the normal nasty plot set. Thundurus-T's only listed set is double dance, but in practice it's coverage isn't good enough to rip through stall if you go double dance and not good enough to deal with glue Pokemon like defensive Rotom-W on otherwise offensive teams if you go double dance either plus it's vulnerable to priority anyway.
My set is:
Thundurus-T@life orb
Ability: volt absorb
EVs: 252 spatk / 4 spdef / 252 spe
Nature: Timid
-Thunder
-hidden power flying
-grass knot
-nasty plot
You can run thunderbolt over thunder, helps you avoid shaky accuracy if you're outside of rain but at the same time also defeats running it in rain at the same time. Grass knot is meant to KO gastrodon/swampert/quagsire, absolutely pivotal for knocking out the premier rain sweeper as well as important bulky waters (I also run specs ashGren Greninja so removing bulky waters is important). Thundurus can destroy a ton of important defensive cores. You annihilate Mega Venusaur cores, defensive Landorus is OHKO'd by HP flying at +2, Celesteela cores eat shit. The ONLY common defensive core it doesn't tear right in half is FerroPex (Ferrothorn is only 2HKO'd by +2 HP flying, but leech seed + protect variants can stall you out potentially) but that's because I run grass knot specifically for bully waters my team needs removed. You can run focus blast and that beats ferrothorn at the cost of...well really just Quagsire/mega swampert (Quagsire is also 2HKO'd by HP flying so you can still sorta deal with it). Chansey is a problem if you pick grass knot over focus blast like I did (you can just boost to +4 against Chansey) so I run knock off on Pelipper to try and trash it's eviolite.
