Games like Contraption Maker
Games like Contraption Maker include Garry's Mod, People Playground, Poly Bridge, Bridge Constructor Portal, and Besiege. We matched them by the tags players give Contraption Maker on Steam (Puzzle, 2D, Lemmings, Sandbox, and Moddable): closest matches first, and among equally close ones the better-known games.

Garry's Mod
Shared: Sandbox · Moddable · Physics

People Playground
Shared: Sandbox · 2D · Moddable

Poly Bridge
Shared: Puzzle · Physics · Sandbox

Bridge Constructor Portal
Shared: Puzzle · 2D · Level Editor

Besiege
Shared: Sandbox · Physics · Simulation

Poly Bridge 2
Shared: Puzzle · Physics · Sandbox

Kerbal Space Program
Shared: Sandbox · Physics · Simulation

Scribblenauts Unlimited
Shared: Puzzle · Sandbox · 2D

Space Engineers
Shared: Sandbox · Physics · Building

Zup! S
Shared: Puzzle · 2D · Physics

Poly Bridge 3
Shared: Puzzle · Level Editor · Physics

Hozy
Shared: Puzzle · Sandbox · Physics

Terraria
Shared: 2D · Sandbox · Building

Opus Magnum
Shared: Puzzle · 2D · Simulation

Crazy Machines 3
Shared: Puzzle · Sandbox · Physics

Baba Is You
Shared: Puzzle · 2D · Indie

World of Goo
Shared: Puzzle · 2D · Physics

Bloons TD 6
Shared: Online Co-Op · Family Friendly · Sandbox

Geometry Dash
Shared: Level Editor · 2D · Colorful

Tricky Towers
Shared: Puzzle · Physics · Family Friendly

Totally Accurate Battle Simulator
Shared: Sandbox · Simulation · Physics

Biped
Shared: Puzzle · Online Co-Op · Sandbox

Cities: Skylines
Shared: Sandbox · Simulation · Moddable

Zup! F
Shared: Puzzle · 2D · Physics