2 stories with ash and serena have great pokemon by starting from kalos where they are OP i wanted to make my version of it here are the stories i meant:
· What if - The complete arc (AshXSerena123)
· Follow Your Dream - Kanto arc (Hero Time 81)

i hope it is still through the rules because i read the rules but see many poeple braking it so i don't know.

only story in chapters not auther notes
(note Pokemon is not mine)

Ashs current pokemon
Greninja
Glaceon
Aegislash
Golurk
Garchomp
Kommo-o
Lucario
Naganadel
Drapion
Houndoom

Serena's current pokemon
Delphox
Primarina
Sylvion
Froslass
Bisharp
Dragonair
Gardevoir
Altaria
Absol
Zorua