I played through
Hoenn (Sapphire)
Kanto (Firered, then Leafgreen)
Sinnoh (Diamond, then Pearl, then Platinum)
Johto (SoulSilver)
Unova (White, then Black)
Unova 1.5 (White 2, then Black 2)
Kalos (Y, then X)
Hoenn 1.5 (Alpha Sapphire, then Omega Ruby)
Alola (Sun, then Moon)
Although, if I'm...