Head smash could be a viable option for fairies since it has more power than steel wing and slighty better accuracy than iron tail, plus it gives him better coverage.
0 Atk Life Orb Hydreigon Head Smash vs. 252 HP / 0 Def Azumarill: 177-208 (43.8 - 51.4%) -- 8.2% chance to 2HKO guaranteed after...