Gen 9 Monotype Defensive (Flying)

Gyarados (M) @ Leftovers
Ability: Intimidate
Tera Type: Water
EVs: 252 HP / 180 Def / 60 SpD / 16 Spe
Impish Nature
- Taunt
- Thunder Wave
- Dragon Tail
- Waterfall
This is the defensive set Gyarados uses on Flying teams in Gen 9 Monotype. This set utilizes Gyarados' Water/Flying typing, utility moves, Ability Intimidate, and 95/79/100 bulk to pull off a defensive set. Taunt allows Gyarados stops defensive Pokemon from using moves such as Toxic, Stealth Rock, Recover, Spikes, as well as stopping slow setup sweepers such as Azumarill from using Belly Drum. Thunder Wave allows Gyarados to spread yellow magic to slow down faster Pokemon, which can be useful for the teammates who aren't that fast. Dragon Tail allows Gyarados to force out opposing Pokemon, which can be useful against setup sweepers that aren't Fairy-types. Waterfall is used for Gyarados' consistent (physical) STAB move that can flinch opposing Pokemon. Leftovers is used for the item to give Gyarados some HP recovery.
252 HP EVs are used for bulk. 16 Speed EVs allow Gyarados to outspeed Azumarill so it can cripple it with Taunt and Thunder Wave. The 60 SpD EVs along with the 252 HP EVs allow Gyarados to avoid a 2HKO from a Choice Specs Protean Ice Beam Greninja. The rest of the EVs are used in defense along with Impish Nature so it can switch into physical attacks more easily.