Games like Ominous!
Games like Ominous! include Undertale, South Park™: The Stick of Truth™, The Henry Stickmin Collection, Finding Paradise, and Yakuza: Like a Dragon. We matched them by the tags players give Ominous! on Steam (RPG, Choose Your Own Adventure, Adventure, Comedy, and Parody ): closest matches first, and among equally close ones the better-known games.

Undertale
Shared: RPG · Multiple Endings · Story Rich

South Park™: The Stick of Truth™
Shared: RPG · Adventure · Comedy

The Henry Stickmin Collection
Shared: Choose Your Own Adventure · Multiple Endings · Funny

Finding Paradise
Shared: Adventure · RPG · Story Rich

Yakuza: Like a Dragon
Shared: RPG · Adventure · JRPG

DELTARUNE
Shared: RPG · Story Rich · Funny

Persona 5 Royal
Shared: RPG · JRPG · Story Rich

OMORI
Shared: RPG · Story Rich · Multiple Endings

South Park™: The Fractured But Whole™
Shared: RPG · Comedy · Funny

Epic Battle Fantasy 5
Shared: Adventure · Funny · RPG

There Is No Game: Wrong Dimension
Shared: Adventure · Comedy · Funny

Impostor Factory
Shared: Adventure · RPG · Story Rich

Metaphor: ReFantazio
Shared: RPG · Adventure · JRPG

Ten Trials of Babel: The Doppelganger Maze
Shared: RPG · Multiple Endings · Choose Your Own Adventure

Persona 4 Golden
Shared: RPG · JRPG · Story Rich

The Witcher 3: Wild Hunt — Remastered
Shared: RPG · Adventure · Story Rich

West of Loathing
Shared: RPG · Comedy · Adventure

Otaku's Adventure
Shared: RPG · Multiple Endings · Funny

Persona 3 Reload
Shared: RPG · JRPG · Story Rich

Shadows Over Loathing
Shared: RPG · Adventure · Choose Your Own Adventure

Tales from the Borderlands
Shared: Adventure · Comedy · Choose Your Own Adventure

The Test
Shared: Choose Your Own Adventure · Multiple Endings · Story Rich

Epic Battle Fantasy 4
Shared: RPG · Adventure · JRPG

OCTOPATH TRAVELER™
Shared: RPG · JRPG · Story Rich