Games like Elysium
Games like Elysium include Mouthwashing, MiSide, No, I'm not a Human, Lost in Vivo, and Phasmophobia. We matched them by the tags players give Elysium on Steam (Idler, Psychological Horror, Horror, Psychological, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

Mouthwashing
Shared: Psychological Horror · Horror · Psychological

MiSide
Shared: Psychological Horror · Horror · Atmospheric

No, I'm not a Human
Shared: Psychological Horror · Horror · Atmospheric

Lost in Vivo
Shared: Psychological Horror · Horror · Psychological

Phasmophobia
Shared: Horror · Psychological Horror · First-Person

Poppy Playtime
Shared: Horror · Psychological Horror · First-Person

Firework
Shared: Horror · Psychological Horror · Atmospheric

Outlast
Shared: Horror · Psychological Horror · Atmospheric

Summer of '58
Shared: Horror · Psychological Horror · Thriller

DISTRAINT: Deluxe Edition
Shared: Psychological Horror · Horror · Pixel Graphics

SILENT HILL 2
Shared: Psychological Horror · Horror · Psychological

Iron Lung
Shared: Horror · Psychological Horror · Atmospheric

Last Report
Shared: Horror · Psychological Horror · Pixel Graphics

FAITH: The Unholy Trinity
Shared: Horror · Psychological Horror · Pixel Graphics

IMSCARED
Shared: Horror · Psychological Horror · Pixel Graphics

Fears to Fathom - Ironbark Lookout
Shared: Psychological Horror · Horror · Atmospheric

Milk inside a bag of milk inside a bag of milk
Shared: Psychological Horror · Horror · Psychological

Little Nightmares II
Shared: Horror · Psychological Horror · Atmospheric

Layers of Fear (2016)
Shared: Psychological Horror · Horror · Atmospheric

INMOST
Shared: Pixel Graphics · Thriller · Atmospheric

Inside the Backrooms
Shared: Horror · Psychological Horror · Atmospheric

Escape the Backrooms
Shared: Horror · Psychological Horror · First-Person

Lethal Company
Shared: Horror · Psychological Horror · First-Person

OMORI
Shared: Psychological Horror · Pixel Graphics · Horror