9 species have Frisk as a hidden ability, 19 as a normal one

Effect, in PokéAPI's words

“Reveals an opponent's held item upon entering battle.”

As a hidden ability

Species	Slot	Note
Wigglytuff	Hidden	Since Generation V
Sentret	Hidden	Since Generation V
Furret	Hidden	Since Generation V
Yanma	Hidden	Since Generation V
Duskull	Hidden	Since Generation V
Dusclops	Hidden	Since Generation V
Yanmega	Hidden	Since Generation V
Dusknoir	Hidden	Since Generation V
Munkidori	Hidden

As a normal ability

Species	Slot	Note
Stantler	Normal
Shuppet	Normal
Banette	Normal
Gothita	Normal
Gothorita	Normal
Gothitelle	Normal
Phantump	Normal
Trevenant	Normal
Pumpkaboo	Normal
Gourgeist	Normal
Noibat	Normal
Noivern	Normal
Orbeetle	Normal
Impidimp	Normal
Morgrem	Normal
Grimmsnarl	Normal
Wyrdeer	Normal
Flittle	Normal
Espathra	Normal

Elsewhere in PokéAPI

10 more holders without a page here

Alternate forms and other species that PokéAPI lists with Frisk.

Pumpkaboo Small, Pumpkaboo Large, Pumpkaboo Super, Gourgeist Small, Gourgeist Large, Gourgeist Super, Exeggutor Alola, Orbeetle Gmax, Grimmsnarl Gmax, Typhlosion Hisui (hidden)