Games like Roots of Insanity
Games like Roots of Insanity include Lucius, Ready or Not, Outlast 2, Outlast, and CARRION. We matched them by the tags players give Roots of Insanity on Steam (Action, Horror, Adventure, Indie, and Gore): closest matches first, and among equally close ones the better-known games.

Lucius
Shared: Horror · Adventure · Gore

Ready or Not
Shared: Horror · FPS · Action

Outlast 2
Shared: Horror · Gore · Psychological Horror

Outlast
Shared: Horror · Gore · Psychological Horror

CARRION
Shared: Action · Gore · Horror

Clive Barker's Hellraiser: Revival
Shared: Action · Gore · Horror

Trepang2
Shared: Horror · Action · Gore

DOOM Eternal
Shared: Action · Gore · FPS

The Beast Inside
Shared: Horror · Adventure · Action

Amnesia: The Dark Descent
Shared: Horror · Gore · Psychological Horror

Blood and Bacon
Shared: Action · Gore · Horror

Remothered: Tormented Fathers
Shared: Action · Horror · Adventure

Maid of Sker
Shared: Horror · Action · Adventure

Resident Evil Village
Shared: Horror · Action · Gore

The Evil Within 2
Shared: Horror · Action · Adventure

Unforgiving - A Northern Hymn
Shared: Horror · Adventure · Indie

Resident Evil 7 Biohazard
Shared: Horror · Gore · Action

Dead by Daylight
Shared: Horror · Gore · Violent

Nightmare of Decay
Shared: Action · Horror · Indie

The Dark Occult
Shared: Action · Horror · Adventure

Atomic Heart
Shared: Adventure · Action · Horror

Serious Sam 4
Shared: Action · Gore · Adventure

Wolfenstein II: The New Colossus
Shared: Action · Gore · FPS

Daymare: 1998
Shared: Action · Horror · Adventure