Games like Mix Universe
Games like Mix Universe include Starbound, Terraria, No Man's Sky, Kerbal Space Program 2, and SpaceEngine. We matched them by the tags players give Mix Universe on Steam (Building, Crafting, Sandbox, Audio Production, and Music-Based Procedural Generation): closest matches first, and among equally close ones the better-known games.
Starbound
Shared: Sandbox · Crafting · Space
Terraria
Shared: Sandbox · Crafting · Building
No Man's Sky
Shared: Space · Sci-fi · Sandbox
Kerbal Space Program 2
Shared: Sandbox · Building · Space
SpaceEngine
Shared: Sandbox · Sci-fi · Space
Kerbal Space Program
Shared: Sandbox · Space · Building
ASTRONEER
Shared: Space · Sandbox · Building
Avorion
Shared: Sandbox · Building · Space
Townscaper
Shared: Building · Sandbox · Relaxing
Rust
Shared: Crafting · Building · Sandbox
Space Engineers
Shared: Building · Sandbox · Space
Stardew Valley
Shared: Sandbox · Crafting · Building
Dyson Sphere Program
Shared: Building · Space · Sandbox
Spaceflight Simulator
Shared: Sandbox · Space · Crafting
Tiny Glade
Shared: Building · Sandbox · Relaxing
The Planet Crafter
Shared: Building · Crafting · Space
Scrap Mechanic
Shared: Building · Sandbox · Crafting
Garry's Mod
Shared: Sandbox · Building · Casual
The Forest
Shared: Crafting · Building · Sandbox
Satisfactory
Shared: Crafting · Building · Sandbox
StarMade
Shared: Sandbox · Building · Space
Starsand Island
Shared: Building · Sandbox · Crafting
TerraTech
Shared: Building · Sandbox · Crafting
SUMMERHOUSE
Shared: Sandbox · Building · Relaxing