Games like Moth Planet
Games like Moth Planet include Hollow Knight, Ori and the Will of the Wisps, Hollow Knight: Silksong, Dead Cells, and Öoo. We matched them by the tags players give Moth Planet on Steam (Metroidvania, 2D Platformer, Collectathon, Platformer, and 2D): closest matches first, and among equally close ones the better-known games.

Hollow Knight
Shared: Metroidvania · Platformer · 2D

Ori and the Will of the Wisps
Shared: Metroidvania · Platformer · Singleplayer

Hollow Knight: Silksong
Shared: Metroidvania · 2D · Platformer

Dead Cells
Shared: Metroidvania · 2D · Adventure

Öoo
Shared: Metroidvania · 2D Platformer · 2D

Momodora: Reverie Under The Moonlight
Shared: Metroidvania · 2D Platformer · 2D

Celeste
Shared: 2D Platformer · Platformer · 2D

ANIMAL WELL
Shared: Metroidvania · Platformer · 2D

Webbed
Shared: 2D Platformer · Cute · 2D

Wuppo: Definitive Edition
Shared: Metroidvania · Platformer · 2D Platformer

Shantae and the Seven Sirens
Shared: Metroidvania · Platformer · 2D

The Messenger
Shared: Metroidvania · Platformer · 2D

F.I.S.T.: Forged In Shadow Torch
Shared: Metroidvania · Platformer · 2D Platformer

Dust: An Elysian Tail
Shared: Metroidvania · Platformer · 2D

Rogue Legacy 2
Shared: Metroidvania · Platformer · Adventure

Nine Sols
Shared: Metroidvania · Platformer · 2D

A Hat in Time
Shared: Collectathon · Cute · Platformer

SHINOBI: Art of Vengeance
Shared: 2D Platformer · Metroidvania · Platformer

Owlboy
Shared: Metroidvania · Platformer · 2D

Islets
Shared: Metroidvania · Platformer · Adventure

Rain World
Shared: Platformer · 2D · 2D Platformer

Yoku's Island Express
Shared: Metroidvania · Platformer · Adventure

Castlevania: Belmont's Curse
Shared: Metroidvania · 2D Platformer · Platformer

Phoenotopia: Awakening
Shared: Metroidvania · Platformer · 2D