Swift Swim
Boosts Speed in rain.
Pokémon with this ability
Horsea
Goldeen
Seaking
Magikarp
Omanyte
Omastar
Kabuto
Kabutops
Qwilfish
Mantine
Kingdra
Lotad
Lombre
Ludicolo
Surskit
Feebas
Huntail
Gorebyss
Relicanth
Luvdisc
As a hidden ability
Not in the game yet
No Pokémon can be obtained with its hidden ability yet, so these are listed for reference.
Psyduck
Golduck
Poliwag
Poliwhirl
Poliwrath
Anorith
ArmaldoAs of v0.75.0 · engine 22ba612f