Games like Umfend
Games like Umfend include MiSide, Poppy Playtime, Sally Face - Episode One, Firewatch, and Layers of Fear (2016). We matched them by the tags players give Umfend on Steam (Indie, Adventure, Horror, Psychological Horror, and First-Person): closest matches first, and among equally close ones the better-known games.

MiSide
Shared: Psychological Horror · Horror · First-Person

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

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

Firewatch
Shared: Adventure · First-Person · Indie

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

Mouthwashing
Shared: Horror · Psychological Horror · Indie

What Remains of Edith Finch
Shared: Adventure · First-Person · Indie

Psychopomp
Shared: Horror · Psychological Horror · Indie

Little Nightmares
Shared: Horror · Adventure · Indie

Outlast
Shared: Horror · First-Person · Psychological Horror

Little Nightmares II
Shared: Adventure · Horror · Psychological Horror

Fran Bow
Shared: Psychological Horror · Horror · Adventure

The Room Two
Shared: Horror · Adventure · Indie

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

Detention
Shared: Indie · Horror · Psychological Horror

Rusty Lake Paradise
Shared: Indie · Adventure · Psychological Horror

Outer Wilds
Shared: Adventure · Indie · Mystery

SOMA
Shared: Horror · Psychological Horror · Atmospheric

Blair Witch
Shared: Adventure · Horror · Indie

The Room
Shared: Adventure · Indie · Mystery

Bendy and the Ink Machine
Shared: Horror · First-Person · Indie

Firework
Shared: Indie · Horror · Psychological Horror

The Room Three
Shared: Adventure · Indie · Mystery

Raging Loop
Shared: Adventure · Indie · Psychological Horror