Games like Restless Nights
Games like Restless Nights include Buckshot Roulette, Outlast, No, I'm not a Human, Ultimate Custom Night, and Five Nights at Freddy's 4. We matched them by the tags players give Restless Nights on Steam (Psychological Horror, Strategy, Horror, Dark, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Buckshot Roulette
Shared: Dark · Horror · Strategy

Outlast
Shared: Horror · Psychological Horror · Atmospheric

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

Ultimate Custom Night
Shared: Horror · Strategy · Singleplayer

Five Nights at Freddy's 4
Shared: Horror · Dark · Psychological Horror

Five Nights at Freddy's 2
Shared: Horror · Psychological Horror · Singleplayer

Outlast 2
Shared: Psychological Horror · Horror · Dark

SOMA
Shared: Psychological Horror · Horror · Atmospheric

Five Nights at Freddy's
Shared: Horror · Psychological Horror · Singleplayer

Poppy Playtime
Shared: Horror · Psychological Horror · Dark

Darkwood
Shared: Horror · Psychological Horror · Dark

Sally Face - Episode One
Shared: Psychological Horror · Horror · Dark

Five Nights at Freddy's 3
Shared: Horror · Psychological Horror · Strategy

MiSide
Shared: Psychological Horror · Horror · Atmospheric

Fran Bow
Shared: Psychological Horror · Horror · Point & Click

Mouthwashing
Shared: Psychological Horror · Horror · Atmospheric

Little Nightmares II
Shared: Horror · Psychological Horror · Dark

Bendy and the Ink Machine
Shared: Horror · Dark · Singleplayer

Little Nightmares
Shared: Horror · Atmospheric · Dark

Five Nights at Freddy's: Sister Location
Shared: Horror · Dark · Strategy

Garten of Banban
Shared: Horror · Psychological Horror · Singleplayer

Resident Evil Village
Shared: Horror · Action · Singleplayer

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

CloverPit
Shared: Psychological Horror · Strategy · Horror