Quoted By:
If only final stages, then
>Grass
Serperior > Torterra > Sceptile > Meganium > Chesnaught > Venusaur > Rillaboom > Decidueye
>Fire
Delphox > Charizard > Blaziken > Typhlosion > Infernape > Incineroar > Cinderace > Emboar
>Water
Empoleon > Samurott > Feraligatr > Blastoise > Primarina > Greninja > Swampert > Inteleon
If any stage is allowed, then
>Grass
Serperior > Torterra > Mega Sceptile > Rowlet > Gigantamax Venusaur > Meganium > Chesnaught > Gigantamax Rillaboom
>Fire
Cyndaquil > Mega Charizard X > Gigantamax Cinderace > Braixen > Blaziken > Infernape > Incineroar > Emboar
>Water
Empoleon > Dewott > Feraligatr > Gigantamax Blastoise > Brionne > Frogadier > Mudkip > Gigantamax Inteleon