11 species have Inner Focus as a hidden ability, 24 as a normal one

Effect, in PokéAPI's words

“Prevents flinching.”

As a hidden ability

Species	Slot	Note
Drowzee	Hidden	Since Generation V
Hypno	Hidden	Since Generation V
Hitmonchan	Hidden	Since Generation V
Kangaskhan	Hidden	Since Generation V
Umbreon	Hidden	Since Generation V
Raikou	Hidden	Since Generation VII
Entei	Hidden	Since Generation VII
Suicune	Hidden	Since Generation VII
Darumaka	Hidden
Mudbray	Hidden
Mudsdale	Hidden

As a normal ability

Species	Slot	Note
Zubat	Normal
Golbat	Normal
Abra	Normal
Kadabra	Normal
Alakazam	Normal
Farfetch’d	Normal
Dragonite	Normal
Crobat	Normal
Girafarig	Normal
Sneasel	Normal
Snorunt	Normal
Glalie	Normal
Riolu	Normal
Lucario	Normal
Throh	Normal
Sawk	Normal
Mienfoo	Normal
Mienshao	Normal
Pawniard	Normal
Bisharp	Normal
Oranguru	Normal
Indeedee	Normal
Kubfu	Normal
Annihilape	Normal

Elsewhere in PokéAPI

3 more holders without a page here

Alternate forms and other species that PokéAPI lists with Inner Focus.

Gallade Mega, Darumaka Galar (hidden), Sneasel Hisui