What is your opinion on Slither Wing? It also has access to STAB First Impression and U-Turn without the need for Tera, and while it doesn't have Dragon Tail, it does have access to Whirlwind. Earthquake is not STAB, but still hit decently hard especially if Sun is up, and it can instead run Fighting STAB such as Close Combat
I really like Slither Wing, but the problem is that for an offensive utility role - Flygon has Levitate, Slither Wing can't avoid Spikes, Webs or Toxic Spikes like Flygon can naturally, it needs Heavy-Duty Boots. Additionally, Flygon takes a negligible amount of damage from Stealth Rock while Slither Wing can't stand repeat switch-ins. Personally, I think the best way to run a Slither Wing set is to run a more offensive trailblaze set.
Slither Wing @ Heavy-Duty Boots
Ability: Protosynthesis
Tera Type: Fire
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Close Combat
- Leech Life
- Temper Flare
- Trailblaze
Here's a set that I like to run. Trailblaze allows Slither Wing to patch up its middling speed and lets Slither Wing dole out powerful attacks. It can force a lot of particularly nasty Pokemon out (including Kingambit) and has a little extra longevity via STAB Leech Life. Temper Flare is to cook Gholdengo switch-ins trying to absorb a Close Combat (Temper Flare doubles in base power from 75 to 150 if the previous move failed).
252+ Atk Slither Wing Temper Flare (75 BP) vs. 0 HP / 0 Def Gholdengo: 192-228 (60.9 - 72.3%) -- guaranteed 2HKO
252+ Atk Tera Fire Slither Wing Temper Flare (75 BP) vs. 0 HP / 0 Def Gholdengo: 288-342 (91.4 - 108.5%) -- 50% chance to OHKO
252+ Atk Slither Wing Temper Flare (150 BP) vs. 0 HP / 0 Def Gholdengo: 384-454 (121.9 - 144.1%) -- guaranteed OHKO
252+ Atk Slither Wing Temper Flare (150 BP) vs. 252 HP / 252+ Def Gholdengo: 274-324 (72.4 - 85.7%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Tera Fire Slither Wing Temper Flare (150 BP) vs. 252 HP / 252+ Def Gholdengo: 410-486 (108.4 - 128.5%) -- guaranteed OHKO
252+ Atk Tera Fire Slither Wing Temper Flare (75 BP) vs. 0 HP / 0 Def Gholdengo: 288-342 (91.4 - 108.5%) -- 50% chance to OHKO
252+ Atk Slither Wing Temper Flare (150 BP) vs. 0 HP / 0 Def Gholdengo: 384-454 (121.9 - 144.1%) -- guaranteed OHKO
252+ Atk Slither Wing Temper Flare (150 BP) vs. 252 HP / 252+ Def Gholdengo: 274-324 (72.4 - 85.7%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Tera Fire Slither Wing Temper Flare (150 BP) vs. 252 HP / 252+ Def Gholdengo: 410-486 (108.4 - 128.5%) -- guaranteed OHKO