Games like Magnet Mania 3D
Games like Magnet Mania 3D include Kerbal Space Program, while True: learn(), PC Building Simulator, Automation - The Car Company Tycoon Game, and Poly Bridge. We matched them by the tags players give Magnet Mania 3D on Steam (Education, Puzzle, Sandbox, Animation & Modeling, and Point & Click): closest matches first, and among equally close ones the better-known games.

Kerbal Space Program
Shared: Sandbox · Education · Space

while True: learn()
Shared: Education · Puzzle · Sandbox

PC Building Simulator
Shared: Education · Sandbox · Management

Automation - The Car Company Tycoon Game
Shared: Sandbox · Management · Education

Poly Bridge
Shared: Puzzle · Sandbox · Education

Universe Sandbox
Shared: Sandbox · Education · Space

Poly Bridge 2
Shared: Puzzle · Sandbox · Education

Universe Sandbox
Shared: Sandbox · Education · Science

Kerbal Space Program 2
Shared: Sandbox · Space · Science

Let's School
Shared: Sandbox · Education · Management

House Flipper
Shared: Sandbox · Education · Simulation

World of Guns: Gun Disassembly
Shared: Education · Animation & Modeling · Software

shapez 2 - Factory
Shared: Puzzle · Management · Sandbox

Space Engineers
Shared: Sandbox · Space · Building

Planet Coaster
Shared: Sandbox · Management · Building

Totally Accurate Battle Simulator
Shared: Sandbox · Simulation · Strategy

Timberborn
Shared: Sandbox · Management · Nature

Cities: Skylines
Shared: Sandbox · Management · Building

Planet Zoo
Shared: Sandbox · Management · Building

Garry's Mod
Shared: Sandbox · Building · Physics

Home Design 3D
Shared: Education · Animation & Modeling · Sandbox

Mini Motorways
Shared: Puzzle · Management · Strategy

SPORE™
Shared: Sandbox · Science · Space

Sandboxels
Shared: Sandbox · Education · Science