"gradient" by Quinton Reeves
    CC-BY-SA 3.0 license, or any later version. Created using the gradient fill tool in GIMP.
    
"stars" by Quinton Reeves
    CC-BY-SA 3.0 license, or any later version. Created with Starbox 1.9 by Alex Grigny de Castro from the included xgStars.txt.
    Generation parameters were set to 0'N / 0'E (Sidereal: 18.299266, or 00:00 July 26th, 2008) which is Red Eclipse's birthday.

"sunsetflat" by LedIris (07/08/2009)
    ZLIB License; Four things that made this skybox; 1:Tarragen 2, 2:Me, 3:Boredom, 4:Being Sick :(
    This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
    * The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
    * Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
    * This notice may not be removed or altered from any source distribution. 

"skyhigh" by Pieter Verhoeven
    CC-BY-SA 3.0 license.

"interstellar", "miramar", and "stormydays" by Jockum "hipshot" Skoglund
    [email protected] / www.zfight.com
    Downloaded from http://opengameart.org/content/interstellar-skybox
    CC-BY 3.0 (Modify however you like, just cred me for my work, maybe link to my page)

"kiara_1_dawn" by Polyhaven

Downloaded from https://polyhaven.com/a/kiara_1_dawn, and converted from HDRI to cubemap 
License: CC0