Games like Sidereal
Games like Sidereal include Funi Raccoon Game, Flower, Monument Valley 3, Antichamber, and Caravan SandWitch. We matched them by the tags players give Sidereal on Steam (Exploration, 3D Platformer, Abstract, Atmospheric, and Colorful): closest matches first, and among equally close ones the better-known games.

Funi Raccoon Game
Shared: 3D Platformer · Exploration · Abstract

Flower
Shared: Atmospheric · Exploration · Immersive

Monument Valley 3
Shared: Atmospheric · Colorful · Abstract

Antichamber
Shared: Exploration · Abstract · Nonlinear

Caravan SandWitch
Shared: Exploration · 3D Platformer · Colorful

Chants of Sennaar
Shared: Colorful · Atmospheric · Exploration

ABZU
Shared: Exploration · Atmospheric · Colorful

My Little Puppy
Shared: Exploration · Colorful · Atmospheric

The Witness
Shared: Exploration · Colorful · Atmospheric

Journey
Shared: Atmospheric · Exploration · Adventure

A Hat in Time
Shared: 3D Platformer · Exploration · Colorful

Pseudoregalia
Shared: 3D Platformer · Exploration · Nonlinear

DREDGE
Shared: Exploration · Atmospheric · Inventory Management

Fallout 4
Shared: Exploration · Atmospheric · Post-apocalyptic

Pumpkin Jack
Shared: 3D Platformer · Colorful · Atmospheric

FAR: Lone Sails
Shared: Atmospheric · Exploration · Post-apocalyptic

Road 96
Shared: Colorful · Atmospheric · Exploration

DARK SOULS™ III
Shared: Atmospheric · Dark Fantasy · Exploration

Moncage
Shared: Atmospheric · Abstract · Exploration

Hypnagogia² 無限の夢 Boundless Dreams
Shared: Exploration · Atmospheric · Abstract

NaissanceE
Shared: Exploration · Abstract · Atmospheric

Slime Rancher
Shared: Exploration · Colorful · Adventure

Bramble: The Mountain King
Shared: Atmospheric · Dark Fantasy · Adventure

RiME
Shared: Exploration · Atmospheric · Colorful