Heh, its the new GyaraVire!
Honestly, I think Goodra rivals Dragonite and Garchomp for the title of best Dragon-type pseudo-legendary. Its stats are perfect, its abilities give it an insane amount of versatility, and its movepool is excellent. Goodra's so well rounded that it can do almost anything.
That said, has anyone tried a Choice Band set? I think we've kinda glossed over just how good base 100 Attack is on this dragon. With Adamant and a Choice Band, Goodra hits 492 Attack. If you manage to grab a Sap Sipper boost, I think it increases to 738. That's insane. If you invest in Speed, Goodra suddenly turns into a frightening wallbreaker:
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 252+ Def Gliscor: 249-294 (70.3 - 83%) -- guaranteed 2HKO
Garchomp, for comparison:
252+ Atk Choice Band Garchomp Outrage vs. 252 HP / 252+ Def Gliscor: 199-235 (56.2 - 66.3%) -- guaranteed 2HKO
Poison Heal saves Gliscor from Garchomp's 2HKO, but not Goodra's. Some more calcs:
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 252+ Def Slowbro: 271-321 (68.7 - 81.4%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Goodra Power Whip vs. 252 HP / 252+ Def Slowbro: 362-428 (91.8 - 108.6%) -- 50% chance to OHKO
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 252+ Def Gourgeist-Super: 253-298 (67.6 - 79.6%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 252+ Def Trevenant: 345-406 (92.2 - 108.5%) -- 50% chance to OHKO
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 252+ Def Rotom-W: 277-327 (91.1 - 107.5%) -- 43.8% chance to OHKO
+1 252+ Atk Choice Band Goodra Power Whip vs. 252 HP / 252+ Def Rotom-W: 370-436 (121.7 - 143.4%) -- guaranteed OHKO
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 252+ Def Skarmory: 114-135 (34.1 - 40.4%)
252 SpA Goodra Fire Blast vs. 252 HP / 0 SpD Skarmory: 286-338 (85.6 - 101.1%) -- 12.5% chance to OHKO
252 SpA Goodra Fire Blast vs. 252 HP / 248+ SpD Ferrothorn: 280-332 (79.5 - 94.3%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 8 Def Ferrothorn: 158-186 (44.8 - 52.8%) -- guaranteed 3HKO after Leftovers recovery
Most Ferrothorn run Rocky Helmet now, so it might hurt, but Goodra could potentially plow right through Ferro.
+1 252+ Atk Choice Band Goodra Outrage vs. 252 HP / 0 Def Heatran: 191-225 (49.4 - 58.2%) -- 64.5% chance to 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Goodra Power Whip vs. 252 HP / 252+ Def Carbink: 290-342 (95.3 - 112.5%) -- 75% chance to OHKO
+1 252+ Atk Choice Band Goodra Aqua Tail vs. 252 HP / 0 Def Togekiss: 210-248 (56.1 - 66.3%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Goodra Rock Slide vs. 252 HP / 0 Def Togekiss: 350-414 (93.5 - 110.6%) -- 62.5% chance to OHKO
+1 252+ Atk Choice Band Goodra Aqua Tail vs. 128 HP / 0 Def Mega Mawile: 167-197 (61.1 - 72.1%) -- guaranteed 2HKO
+1 252+ Atk Choice Band Goodra Earthquake vs. 128 HP / 0 Def Mega Mawile: 370-436 (135.5 - 159.7%) -- guaranteed OHKO
And so on. With a boost, Goodra 2HKOs the entire metagame bar Skarmory. Considering how common Grass-type moves are, this set definitely has some merit.
Goodra
Choice Band
Adamant / Lonely (- Def for mixed sets)
Sap Sipper
4 HP / 252 Atk / 252 Spe
Outrage
Power Whip
Aqua Tail
Earthquake / Rock Slide / Fire Blast