Games like Solar System
Games like Solar System include Mountain, SPACEPLAN, Solar 2, Drifter Star: Evolution, and Defy Gravity Extended. We matched them by the tags players give Solar System on Steam (Indie, Casual, and Space): closest matches first, and among equally close ones the better-known games.

Mountain
Shared: Indie · Casual · Space

SPACEPLAN
Shared: Casual · Indie · Space

Solar 2
Shared: Indie · Space · Casual

Drifter Star: Evolution
Shared: Casual · Indie · Space

Defy Gravity Extended
Shared: Indie · Space · Casual

Out of Space
Shared: Casual · Indie · Space

Cookie Clicker
Shared: Casual · Indie

FTL: Faster Than Light
Shared: Space · Indie

Florence
Shared: Indie · Casual

Cyberhunt
Shared: Indie · Casual · Space

Waveform
Shared: Indie · Casual · Space

Golf With Your Friends
Shared: Casual · Indie

Liars Bar
Shared: Casual · Indie

Donut County
Shared: Indie · Casual

Game Dev Tycoon
Shared: Indie · Casual

Starbound
Shared: Space · Indie · Casual

Assemble with Care
Shared: Indie · Casual

Zup! S
Shared: Casual · Indie

Little Inferno
Shared: Indie · Casual

LOCKDOWN Protocol
Shared: Space · Casual · Indie

Beyond Gravity
Shared: Casual · Indie · Space

Pikuniku
Shared: Indie · Casual

Space Pilgrim Episode I: Alpha Centauri
Shared: Space · Indie · Casual

Stellar 2D
Shared: Indie · Casual · Space