Games like Invincible Fins
Games like Invincible Fins include Slime Rancher, Webbed, Stray, Hollow Knight, and A Hat in Time. We matched them by the tags players give Invincible Fins on Steam (Adventure, Exploration, Underwater, Cute, and Colorful): closest matches first, and among equally close ones the better-known games.

Slime Rancher
Shared: Exploration · Adventure · Cute

Webbed
Shared: Cute · Exploration · 2D Platformer

Stray
Shared: Adventure · Exploration · Cute

Hollow Knight
Shared: Exploration · Adventure · Platformer

A Hat in Time
Shared: Cute · Adventure · Exploration

A Short Hike
Shared: Exploration · Adventure · Cute

ABZU
Shared: Underwater · Exploration · Adventure

Cat Goes Fishing
Shared: Cute · Exploration · Underwater

Hollow Knight: Silksong
Shared: Exploration · Adventure · Indie

Carto
Shared: Exploration · Cute · Adventure

Pizza Tower
Shared: 2D Platformer · Cartoony · Indie

Ori and the Will of the Wisps
Shared: Adventure · Exploration · Singleplayer

Thank Goodness You're Here!
Shared: Adventure · Exploration · 2D Platformer

Rain World
Shared: Exploration · Adventure · Indie

Bugsnax
Shared: Adventure · Cute · Singleplayer

Subnautica: Below Zero
Shared: Underwater · Exploration · Singleplayer

Celeste
Shared: 2D Platformer · Adventure · Indie

DAVE THE DIVER
Shared: Adventure · Exploration · Underwater

Subnautica
Shared: Underwater · Exploration · Adventure

Chants of Sennaar
Shared: Adventure · Colorful · Singleplayer

Neva
Shared: Adventure · Colorful · Indie

Loddlenaut
Shared: Underwater · Cute · Adventure

Monster Boy and the Cursed Kingdom
Shared: Adventure · Exploration · Indie

Slime Rancher 2
Shared: Cute · Adventure · Colorful