Games like Plasma
Games like Plasma include Satisfactory, Stormworks: Build and Rescue, Out of Ore, Mon Bazou, and Avorion. We matched them by the tags players give Plasma on Steam (Simulation, Sandbox, 3D, Exploration, and Building): closest matches first, and among equally close ones the better-known games.

Satisfactory
Shared: Sandbox · Automation · Building

Stormworks: Build and Rescue
Shared: Sandbox · Building · Exploration

Out of Ore
Shared: Simulation · Sandbox · Exploration

Mon Bazou
Shared: Sandbox · Exploration · Choose Your Own Adventure

Avorion
Shared: Sandbox · Exploration · Building

Garry's Mod
Shared: Sandbox · Building · Simulation

Dyson Sphere Program
Shared: Simulation · Building · Automation

Space Engineers
Shared: Sandbox · Simulation · Building

Kerbal Space Program
Shared: Simulation · Sandbox · Building

Fireworks Mania - An Explosive Simulator
Shared: Sandbox · Exploration · Building

PC Building Simulator
Shared: Simulation · Sandbox · Building

shapez 2 - Factory
Shared: Simulation · Building · Sandbox

Scrap Mechanic
Shared: Sandbox · Building · First-Person

SimplePlanes
Shared: Sandbox · Building · Exploration

Aviassembly
Shared: Sandbox · Building · Exploration

Internet Cafe Simulator 2
Shared: Simulation · 3D · Exploration

Kerbal Space Program 2
Shared: Sandbox · Exploration · Building

Schedule I
Shared: Simulation · First-Person · Building

Techtonica
Shared: Simulation · Building · Exploration

The Forest
Shared: Building · Sandbox · Exploration

Hydroneer
Shared: Sandbox · Automation · Simulation

Terraria
Shared: Sandbox · Building · Exploration

Empyrion - Galactic Survival
Shared: Simulation · Building · Exploration

Sandustry
Shared: Sandbox · Building · Exploration