2 species have Minus as a hidden ability, 4 as a normal one

Effect, in PokéAPI's words

“Increases Special Attack to 1.5× when a friendly Pokémon has Plus or Minus.”

As a hidden ability

Species	Slot	Note
Electrike	Hidden	Since Generation V
Manectric	Hidden	Since Generation V

As a normal ability

Species	Slot	Note
Minun	Normal
Klink	Normal
Klang	Normal
Klinklang	Normal

Elsewhere in PokéAPI

2 more holders without a page here

Alternate forms and other species that PokéAPI lists with Minus.

Toxtricity Low Key, Toxtricity Low Key Gmax