Games like Phasmonauts
Games like Phasmonauts include Phasmophobia, Content Warning, The Painscreek Killings, PEAK, and We Were Here. We matched them by the tags players give Phasmonauts on Steam (Action Roguelike, Supernatural, Horror, Exploration, and Multiplayer): closest matches first, and among equally close ones the better-known games.

Phasmophobia
Shared: Horror · Multiplayer · Supernatural

Content Warning
Shared: Horror · Action Roguelike · Exploration

The Painscreek Killings
Shared: Investigation · Exploration · Mystery

PEAK
Shared: Multiplayer · Exploration · Action Roguelike

We Were Here
Shared: Horror · Multiplayer · Puzzle

Pacify
Shared: Horror · Multiplayer · Exploration

Inside the Backrooms
Shared: Horror · Multiplayer · Puzzle

Ghost Exorcism INC.
Shared: Horror · Supernatural · Multiplayer

Enigma of Fear
Shared: Supernatural · Investigation · Mystery

Backrooms: Escape Together
Shared: Horror · Multiplayer · Exploration

Murdered: Soul Suspect
Shared: Supernatural · Horror · Mystery

Labyrinthine
Shared: Horror · Multiplayer · Supernatural

Outer Wilds
Shared: Exploration · Mystery · Puzzle

Subnautica 2
Shared: Horror · Multiplayer · Exploration

Murders on the Yangtze River
Shared: Puzzle · Exploration · Mystery

Escape the Backrooms
Shared: Horror · Multiplayer · Exploration

ANIMAL WELL
Shared: Exploration · Horror · Puzzle

The Mortuary Assistant
Shared: Supernatural · Horror · Mystery

R.E.P.O.
Shared: Horror · Multiplayer · Exploration

Blue Prince
Shared: Exploration · Mystery · Puzzle

Firework
Shared: Horror · Puzzle · Mystery

The Vanishing of Ethan Carter
Shared: Mystery · Exploration · Horror

Strange Horticulture
Shared: Mystery · Puzzle · Investigation

Lorelei and the Laser Eyes
Shared: Horror · Exploration · Puzzle