Games like Kasmo
Games like Kasmo include Garry's Mod, Donut County, Berry Bury Berry, Getting Over It with Bennett Foddy, and Zup! S. We matched them by the tags players give Kasmo on Steam (Singleplayer, Physics, 3D, Casual, and Isometric): closest matches first, and among equally close ones the better-known games.

Garry's Mod
Shared: Physics · Singleplayer · Casual

Donut County
Shared: Casual · Physics · Indie

Berry Bury Berry
Shared: 3D · Physics · Singleplayer

Getting Over It with Bennett Foddy
Shared: Singleplayer · Physics · Casual

Zup! S
Shared: Casual · Physics · Singleplayer

Teardown
Shared: Physics · Singleplayer · Indie

Sizeable
Shared: Casual · Singleplayer · Indie

Totally Accurate Battle Simulator
Shared: Physics · Singleplayer · Indie

Goat Simulator
Shared: Physics · Casual · Singleplayer

Gang Beasts
Shared: Physics · Singleplayer · Casual

Golf With Your Friends
Shared: Casual · Singleplayer · Indie

World of Goo
Shared: Physics · Singleplayer · Indie

People Playground
Shared: Physics · Singleplayer · Indie

Mirror 2: Project X
Shared: 3D · Singleplayer · Casual

Bloons TD 6
Shared: Singleplayer · Casual · 3D

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

Superflight
Shared: Casual · Singleplayer · Indie

STANDBOX
Shared: Physics · 3D · Singleplayer

Game Dev Tycoon
Shared: Singleplayer · Casual · Indie

Cooking Simulator VR
Shared: Casual · Physics · Singleplayer

Zup!
Shared: Casual · Physics · Indie

MUSYNX
Shared: Singleplayer · Casual · Indie

DrainSim
Shared: Casual · Physics · 3D

RV There Yet?
Shared: Physics · 3D · Indie