Games like Lillysia
Games like Lillysia include Celeste, Dust: An Elysian Tail, SANABI, Hollow Knight: Silksong, and Super Meat Boy. We matched them by the tags players give Lillysia on Steam (Adventure, Action, Platformer, Precision Platformer, and 2D): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Precision Platformer · Platformer · Indie

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

SANABI
Shared: Action · Adventure · 2D

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

Super Meat Boy
Shared: Platformer · Precision Platformer · 2D

Hollow Knight
Shared: Platformer · 2D · Adventure

Jump King
Shared: Precision Platformer · Adventure · Platformer

ICEY
Shared: Action · Adventure · Female Protagonist

Tomb Raider Game of the Year
Shared: Adventure · Action · Female Protagonist

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

Shovel Knight: Treasure Trove
Shared: Platformer · Adventure · Action

Skul: The Hero Slayer
Shared: Action · 2D · Indie

Planet of Lana
Shared: Action · Female Protagonist · Adventure

The End Is Nigh
Shared: Platformer · Precision Platformer · Adventure

The Vagrant
Shared: Action · 2D · Adventure

VVVVVV
Shared: Platformer · Precision Platformer · Indie

Neva
Shared: Adventure · Platformer · Indie

Rise of the Tomb Raider™
Shared: Adventure · Action · Female Protagonist

GRIS
Shared: Adventure · Platformer · Female Protagonist

Rogue Legacy
Shared: Platformer · Action · 2D

Downwell
Shared: Precision Platformer · Platformer · Action

SteamWorld Dig 2
Shared: Adventure · Action · Platformer

Phoenotopia: Awakening
Shared: Adventure · Action · Platformer

Owlboy
Shared: Adventure · Platformer · 2D