Games like Project P.I.T.T.
Games like Project P.I.T.T. include Garry's Mod, Berry Bury Berry, People Playground, Teardown, and GoreBox. We matched them by the tags players give Project P.I.T.T. on Steam (Physics, Incremental, Sandbox, Automation, and Capitalism): closest matches first, and among equally close ones the better-known games.

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

Berry Bury Berry
Shared: Incremental · Physics · First-Person

People Playground
Shared: Physics · Sandbox · Simulation

Teardown
Shared: Physics · Sandbox · First-Person

GoreBox
Shared: Sandbox · Physics · First-Person

Totally Accurate Battle Simulator
Shared: Sandbox · Physics · Simulation

Goat Simulator
Shared: Physics · Sandbox · Simulation

SuchArt: Creative Space
Shared: Sandbox · Physics · First-Person

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

DrainSim
Shared: Physics · Sandbox · First-Person

BeamNG.drive
Shared: Physics · Sandbox · Simulation

BONEWORKS
Shared: Physics · Sandbox · First-Person

Leaf it Alone
Shared: Incremental · Physics · Casual

PowerWash Simulator
Shared: Casual · Sandbox · First-Person

Graveyard Keeper 2
Shared: Sandbox · Capitalism · Automation

Noita
Shared: Physics · Sandbox · Pixel Graphics

Cash Cleaner Simulator
Shared: Sandbox · Automation · Physics

Recycling Center Simulator
Shared: First-Person · Automation · Sandbox

Fun with Ragdolls: The Game
Shared: Physics · Sandbox · 3D

BONELAB
Shared: Physics · Sandbox · First-Person

Cooking Simulator
Shared: Sandbox · Physics · Simulation

Goat Simulator 3
Shared: Physics · Sandbox · 3D

Kerbal Space Program
Shared: Physics · Sandbox · Simulation

Hot Dogs, Horseshoes & Hand Grenades
Shared: Sandbox · Physics · First-Person