Games like Pony Island
Games like Pony Island include OneShot, Sally Face - Episode One, DISTRAINT: Deluxe Edition, Little Nightmares II, and Little Nightmares. We matched them by the tags players give Pony Island on Steam (Puzzle, Indie, Psychological Horror, Pixel Graphics, and Hacking): closest matches first, and among equally close ones the better-known games.

OneShot
Shared: Indie · Pixel Graphics · Puzzle

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

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

Little Nightmares II
Shared: Puzzle · Singleplayer · Horror

Little Nightmares
Shared: Puzzle · Horror · Singleplayer

Poppy Playtime
Shared: Puzzle · Singleplayer · Horror

OMORI
Shared: Psychological Horror · Indie · Pixel Graphics

Firework
Shared: Indie · Puzzle · Psychological Horror

Fran Bow
Shared: Psychological Horror · Puzzle · Indie

Undertale
Shared: Pixel Graphics · Indie · Great Soundtrack

Changed
Shared: Puzzle · Psychological Horror · Pixel Graphics

The Hex
Shared: Indie · Psychological Horror · Singleplayer

The Witch's House MV
Shared: Indie · Pixel Graphics · Psychological Horror

Papers, Please
Shared: Indie · Pixel Graphics · Puzzle

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

Please, Don’t Touch Anything
Shared: Puzzle · Indie · Pixel Graphics

Detention
Shared: Indie · Psychological Horror · Puzzle

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

Replica
Shared: Indie · Puzzle · Pixel Graphics

LIMBO
Shared: Indie · Puzzle · Dark

IMSCARED
Shared: Indie · Psychological Horror · Pixel Graphics

There Is No Game: Wrong Dimension
Shared: Puzzle · Indie · Pixel Graphics

Gunpoint
Shared: Indie · Puzzle · Pixel Graphics

Rusty Lake Paradise
Shared: Puzzle · Indie · Psychological Horror