Games like Butterfly Project
Games like Butterfly Project include Mountain, Kabuto Park, Slime Rancher 2, Leaf it Alone, and Spirit City: Lofi Sessions. We matched them by the tags players give Butterfly Project on Steam (Casual, Simulation, Creature Collector, Cozy, and Relaxing): closest matches first, and among equally close ones the better-known games.

Mountain
Shared: Simulation · Casual · Relaxing

Kabuto Park
Shared: Casual · Creature Collector · Cozy

Slime Rancher 2
Shared: Relaxing · Creature Collector · Singleplayer

Leaf it Alone
Shared: Simulation · Casual · Relaxing

Spirit City: Lofi Sessions
Shared: Cozy · Relaxing · Creature Collector

Tiny Glade
Shared: Relaxing · Casual · Cozy

Creature Kitchen
Shared: Creature Collector · Cozy · Relaxing

Cast n Chill
Shared: Relaxing · Cozy · Creature Collector

Equilinox
Shared: Simulation · Casual · Relaxing

House Flipper
Shared: Simulation · Casual · Relaxing

Potion Craft: Alchemist Simulator
Shared: Simulation · Relaxing · Singleplayer

Sticky Business
Shared: Casual · Simulation · Relaxing

Spilled!
Shared: Casual · Relaxing · Cozy

Passpartout: The Starving Artist
Shared: Casual · Simulation · Relaxing

Unpacking
Shared: Casual · Relaxing · Simulation

Leafy Corner
Shared: Casual · Cozy · Simulation

Mini Motorways
Shared: Simulation · Casual · Relaxing

Dressmaker
Shared: Cozy · Simulation · Casual

Garden Life: A Cozy Simulator
Shared: Simulation · Casual · Relaxing

Tiny Bookshop
Shared: Cozy · Casual · Relaxing

Luma Island
Shared: Casual · Cozy · Simulation

Paralives
Shared: Simulation · Indie · Casual

LEGO® Builder's Journey
Shared: Casual · Relaxing · Indie

PowerWash Simulator
Shared: Casual · Simulation · Relaxing

