Games like Lunara: Planet IX
Games like Lunara: Planet IX include Terraria, Forager, Starbound, Core Keeper, and The Forest. We matched them by the tags players give Lunara: Planet IX on Steam (Adventure, Pixel Graphics, 2D, Female Protagonist, and Collectathon): closest matches first, and among equally close ones the better-known games.

Terraria
Shared: 2D · Pixel Graphics · Adventure

Forager
Shared: Pixel Graphics · Survival · Adventure

Starbound
Shared: Adventure · Survival · Pixel Graphics

Core Keeper
Shared: Pixel Graphics · Survival · Exploration

The Forest
Shared: Adventure · Survival · Crafting

DAVE THE DIVER
Shared: Pixel Graphics · Adventure · Exploration

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

Rust
Shared: Survival · Crafting · Adventure

Sons Of The Forest
Shared: Survival · Adventure · Crafting

Necesse
Shared: Pixel Graphics · Adventure · Survival

Rain World
Shared: Pixel Graphics · Survival · Exploration

Valheim
Shared: Survival · Adventure · Crafting

Don't Starve Together
Shared: Adventure · Survival · Crafting

Once Human
Shared: Survival · Adventure · Exploration

The Escapists
Shared: Pixel Graphics · 2D · Crafting

ARK: Survival Evolved
Shared: Survival · Adventure · Crafting

Don't Starve
Shared: Adventure · Survival · Crafting

Keplerth
Shared: Adventure · Exploration · Survival

Satisfactory
Shared: Crafting · Adventure · Exploration

ARK: Survival Ascended
Shared: Survival · Adventure · Crafting

Noita
Shared: Pixel Graphics · 2D · Dungeon Crawler

Subnautica
Shared: Survival · Adventure · Exploration

Oxygen Not Included
Shared: Survival · 2D · Building

Enshrouded
Shared: Survival · Adventure · Crafting