A series of 64 FREE Procedurally Generated Skyboxes you can use as backgrounds or images in your games or projects! 

Great for First Person Shooters, Battle Arenas, RPGs, or anywhere you need a Skybox! These skyboxes are based on the Planet Surface themes in the Planet Surface Backgrounds 2 pack on Itch.io. All Planet Surface Skyboxes have been rendered and exported using custom scripting, then manually stitched into cubemaps or equirectangular panoramas. Every background has been rendered as *.png using two Skybox styles, Cubemap or Panorama, so you can choose the type that best fits your needs! Each environment comes with at least 2 different styles, or night and day renders, allowing for more variety.

Cubemap skyboxes have been rendered using 512x512 frames and assembled into 2048x1536 horizontal cross cubemaps, but can easily be split into individual frames.

Panorama (spherically mapped / equirectangular) skyboxes have all been rendered at 2048x1024.

Downloads have been split into separate packs containing either Cubemap or Panorama style skyboxes, with 32 skybox files contained in each pack.

Contents:

64 Planet Surface Skyboxes (32 Cubemap / 32 Panorama)

• 4 x Cratered Planet Skyboxes
• 4 x Desert Planet Skyboxes
• 4 x Hazy Planet Skyboxes
• 4 x Icy Planet Skyboxes
• 4 x Island Planet Skyboxes
• 4 x Lava Planet Skyboxes
• 4 x Lush Planet Skyboxes
• 4 x Mars Planet Skyboxes
• 4 x Methane Planet Skyboxes
• 4 x Ocean Planet Skyboxes
• 4 x Plains Planet Skyboxes
• 4 x Red Planet Skyboxes
• 4 x Rocky Planet Surfaces
• 4 x Snowy Planet Surfaces
• 4 x Temperate Planet Surfaces
• 4 x Tropical Planet Surfaces

That's 32 Planet Surfaces rendered using 2 Projections for a total of 64 Planet Surface Skyboxes in total! 

All assets in this pack have been released under the Public Domain (CC0) license and are free to use however you like in any project, commercial or non-commercial.