Games like Droneboi: Conquest
Games like Droneboi: Conquest include Avorion, Kerbal Space Program, Space Engineers, Kerbal Space Program 2, and Terraria. We matched them by the tags players give Droneboi: Conquest on Steam (Choose Your Own Adventure, Exploration, Sandbox, 2D Platformer, and Building): closest matches first, and among equally close ones the better-known games.

Avorion
Shared: Exploration · Sandbox · Building

Kerbal Space Program
Shared: Sandbox · Space · Building

Space Engineers
Shared: Sandbox · Building · Space

Kerbal Space Program 2
Shared: Exploration · Sandbox · Space

Terraria
Shared: Sandbox · Exploration · Building

EVE Online
Shared: Exploration · Space · Sandbox

Elite Dangerous
Shared: Exploration · Space · Space Sim

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

Empyrion - Galactic Survival
Shared: Space · Exploration · Building

No Man's Sky
Shared: Exploration · Space · Sandbox

Starbound
Shared: Sandbox · Space · Exploration

X4: Foundations
Shared: Exploration · Space · Sandbox

Garry's Mod
Shared: Sandbox · Building · Physics

Spaceflight Simulator
Shared: Sandbox · Exploration · Space

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

Dyson Sphere Program
Shared: Building · Space · Automation

People Playground
Shared: Sandbox · Physics · Building

ASTRONEER
Shared: Exploration · Space · Sandbox

SPORE™
Shared: Sandbox · Exploration · Space

Satisfactory
Shared: Automation · Building · Sandbox

SimplePlanes
Shared: Sandbox · Exploration · Building

Rust
Shared: Building · Sandbox · PvP

Starbase
Shared: Building · Sandbox · Space

Starminer
Shared: Sandbox · Economy · Exploration