This is a collection of resources and software that I have found useful for 3D artists in one way or another. Some are free and some are paid resources.
Free to use cc0 or no attribution resources
Textures
https://yethiel.wordpress.com/cc0-textures/ this is a 5gb package of textures to download
http://www.chocofur.com/ got high quality textures only requirement is to create an account to download them. cc0
http://duion.com/art/main this is a library of cc0 textures. Mostly photos that is taken to be used as textures, not properly prepared to be seamless or anything though so they need some work.
Images
https://pixabay.com/ only cc0 images, larges library and fast growing
https://stocksnap.io cc0 images, smaller library, may find more unique images here
https://www.pexels.com/ like the two above I guess
https://unsplash.com not cc0 but very close only real difference is that you cant bulk download to create your own image site
Icons
https://iconmonstr.com/ it’s not cc0, can’t be used in logos etc. but a very permitting license.
HDRI
Blender News
https://www.blendernation.com/
https://blender.community/c/today/
Game Engines
https://aws.amazon.com/lumberyard/
2D Image
https://www.madewithmischief.com/
3D Image
https://www.marvelousdesigner.com/
https://pro.radeon.com/en/software/prorender/
For streaming and video
Texture Work
https://www.allegorithmic.com/ Substance Suite
http://frozenflamecorp.com Mindtex2
Art tools
http://kruelgames.com/tools/kuadro/ Reference image manager
https://www.fonts.com/web-fonts/google Google Font manager
Photography
http://digicamcontrol.com/download