Games like Night at the Office
Games like Night at the Office include No, I'm not a Human, Mouthwashing, SOMA, MiSide, and Layers of Fear (2016). We matched them by the tags players give Night at the Office on Steam (Horror, Walking Simulator, Story Rich, Psychological Horror, and Multiple Endings): closest matches first, and among equally close ones the better-known games.

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

Mouthwashing
Shared: Horror · Psychological Horror · Story Rich

SOMA
Shared: Horror · Psychological Horror · Story Rich

MiSide
Shared: Psychological Horror · Story Rich · Horror

Layers of Fear (2016)
Shared: Horror · Walking Simulator · Psychological Horror

Still Wakes the Deep
Shared: Horror · Psychological Horror · Walking Simulator

Amnesia: A Machine For Pigs
Shared: Horror · Walking Simulator · Story Rich

Fears to Fathom - Norwood Hitchhike
Shared: Horror · Psychological Horror · Story Rich

Fears to Fathom - Ironbark Lookout
Shared: Horror · Psychological Horror · Walking Simulator

Summer of '58
Shared: Horror · Walking Simulator · Psychological Horror

What Remains of Edith Finch
Shared: Story Rich · Walking Simulator · Psychological Horror

THRESHOLD
Shared: Horror · Psychological Horror · Walking Simulator

OMORI
Shared: Story Rich · Psychological Horror · Horror

Crimson Snow (2023)
Shared: Horror · Walking Simulator · Psychological Horror

While We Wait Here
Shared: Horror · Walking Simulator · Psychological Horror

Visage
Shared: Horror · Psychological Horror · Dark

Five Nights at Freddy's: Security Breach
Shared: Horror · Multiple Endings · Story Rich

The Inn-Sanity
Shared: Horror · Walking Simulator · Psychological Horror

35MM
Shared: Walking Simulator · Horror · Hidden Object

Phasmophobia
Shared: Horror · Psychological Horror · Dark

Firewatch
Shared: Story Rich · Walking Simulator · Horror

The Coffin of Andy and Leyley
Shared: Story Rich · Multiple Endings · Psychological Horror

Sally Face - Episode One
Shared: Story Rich · Horror · Psychological Horror

Layers of Fear 2 (2019)
Shared: Horror · Psychological Horror · Walking Simulator