Games like Timeless Rain
Games like Timeless Rain include Hollow Knight, Hollow Knight: Silksong, Nine Sols, Celeste, and Ori and the Will of the Wisps. We matched them by the tags players give Timeless Rain on Steam (Metroidvania, Hand-drawn, Story Rich, Adventure, and Difficult): closest matches first, and among equally close ones the better-known games.

Hollow Knight
Shared: Metroidvania · Platformer · Difficult

Hollow Knight: Silksong
Shared: Metroidvania · Difficult · Singleplayer

Nine Sols
Shared: Metroidvania · Difficult · Hand-drawn

Celeste
Shared: Difficult · Precision Platformer · Platformer

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

MIO: Memories in Orbit
Shared: Metroidvania · Platformer · Singleplayer

SANABI
Shared: Story Rich · Adventure · Singleplayer

Geometry Dash
Shared: Difficult · Singleplayer · Platformer

GRIS
Shared: Hand-drawn · Adventure · Platformer

Dust: An Elysian Tail
Shared: Metroidvania · Platformer · Adventure

Night in the Woods
Shared: Story Rich · Adventure · Stylized

Constance
Shared: Metroidvania · Platformer · Hand-drawn

Super Meat Boy
Shared: Difficult · Platformer · Precision Platformer

Rain World
Shared: Difficult · Platformer · Adventure

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

Blasphemous 2
Shared: Metroidvania · Difficult · Adventure

Dead Cells
Shared: Metroidvania · Adventure · 2D

Rogue Legacy 2
Shared: Metroidvania · Platformer · Adventure

Aeterna Noctis
Shared: Metroidvania · Difficult · Platformer

Unbound: Worlds Apart
Shared: Adventure · Metroidvania · Platformer

Owlboy
Shared: Adventure · Metroidvania · Platformer

Blasphemous
Shared: Metroidvania · Difficult · 2D

Cave Story+
Shared: Metroidvania · Difficult · Platformer

Cuphead
Shared: Difficult · Platformer · Hand-drawn