Games like Space Tourist
Games like Space Tourist include Elite Dangerous, Slime Rancher, No Man's Sky, SpaceEngine, and PowerWash Simulator. We matched them by the tags players give Space Tourist on Steam (3D, Simulation, Cartoony, First-Person, and Stylized): closest matches first, and among equally close ones the better-known games.

Elite Dangerous
Shared: Simulation · Sci-fi · Space Sim

Slime Rancher
Shared: First-Person · Adventure · Simulation

No Man's Sky
Shared: Sci-fi · First-Person · Adventure

SpaceEngine
Shared: Sci-fi · 3D · Casual

PowerWash Simulator
Shared: Simulation · 3D · Casual

X4: Foundations
Shared: Simulation · Sci-fi · Space Sim

Internet Cafe Simulator 2
Shared: Simulation · 3D · First-Person

Slime Rancher 2
Shared: First-Person · Simulation · Singleplayer

Hardspace: Shipbreaker
Shared: Simulation · Sci-fi · First-Person

House Flipper
Shared: Simulation · Singleplayer · Casual

SPORE™
Shared: Simulation · Sandbox · Casual

Starfield
Shared: Sci-fi · First-Person · Singleplayer

Kerbal Space Program
Shared: Simulation · Sandbox · Space Sim

The Long Dark
Shared: First-Person · Simulation · Adventure

Fallout 4
Shared: Singleplayer · Adventure · First-Person

PC Building Simulator
Shared: Simulation · 3D · First-Person

Thief Simulator
Shared: Simulation · First-Person · Singleplayer

Goat Simulator 3
Shared: Simulation · 3D · Sandbox

Fireworks Mania - An Explosive Simulator
Shared: 3D · Sandbox · Singleplayer

SuchArt: Creative Space
Shared: Simulation · First-Person · Singleplayer

Garry's Mod
Shared: First-Person · Sandbox · Simulation

Universe Sandbox
Shared: Simulation · Sandbox · Space Sim

X Rebirth
Shared: Simulation · Sci-fi · Singleplayer

Out of Ore
Shared: Simulation · 3D · First-Person