Sunny Day Flygon
Sunny Day
Solarbeam
Flamethrower
Earth Power/ Dragon Pulse
Item: Life Orb
Ability: Levitate
Nature: Modest
EVs: 252 Special Attack/ 6 Special Defense/ 252 Speed
This set is based around drawing out a certain threat and removing it. Choice Scarf Flygon is all too popular today, so send this Flygon in EARLY GAME for a revenge kill on a pokemon that is relatively healthy (so that the opponent will switch it out). The opponent will switch in something to counter Flygon, expecting to see Flygon U-turn away. However, this set will use Sunny Day on the switch, and then proceed to KO the opponent's switch-in. Life Orb and Modest is used here to hit harder and prevent the sun from hindering your team later on. Timid can be used to speed tie +natured base 100s, but keep in mind that Bulky Gyarados will nearly always beat you.
Damage Calculations v. common Flygon counters (in the sun):
Solarbeam on
Suicune (Crocune): 58.9% - 69.8% (2HKO)
Solarbeam on
Vaporeon (Standard Wish Support): 62.9% - 74.1% (2HKO)
Dragon Pulse on
Gliscor (Stallbreaker): 54.5% - 64.4% (2HKO)
Solarbeam on
Hippowdon (Physical Wall): 74.8% - 88.1% (2HKO)
Solarbeam on
Swampert (CursePert): 100% (OHKO)
Flamethrower on
Skarmory (Spiker): 100% (OHKO)
Flamethrower on
Forretress (Spiker): 100% (OHKO)
None of the above pokemon have anything that can touch Flygon in the sun unless:
1) Suicune/ Vaporeon have Ice Beam
2) Hippowdon has Ice Fang
3) Specially defensive Skarmory may survive a Flamethrower even with Stealth Rock (94% - 110.8%).
Damage Calculations v. switch-ins expecting U-Turn:
Dragon Pulse on
Gyarados (Bulky Dragon Dance): 40.8% - 48.1% (With Leftovers and Stealth Rock, Flygon has a good chance to 2HKO)
Earth Power on
Heatran (Any set): 100% (OHKO)
Dragon Pulse on
Dragonite (Dragon Dance): 78.2% - 92.2% (High Chance to OHKO with Stealth Rock and Leftovers factored in)
Overview: This Flygon can act as a revenge killer to draw out the opponent's wall and proceed to KO the wall. Any sweeper that does will with Suicune, Vaporeon, Swampert, Skarmory, Heatran, and Gliscor gone will definitely benefit from this Flygon.
Dragon Pulse or Earth Power?
If Gliscor, Gyarados, or Dragonite are more problematic to your team, then Dragon Pulse is the better option. However, this leaves you completely walled by Heatran. If your team can handle Heatran easily, then Dragon Pulse is better.