Many times I have seen people asking about it where you can search for free graphics, music or other game items. I decided to prepare a small list.
Kenney.nl at this address we find a collection of mainly 2d graphics and several 3d and some sounds. The graphics are made in a colourful and pleasant climate.
Opengameart.org is a huge collection of graphics (2d and 3d), sounds, music, textures. You will also find a fairly rich and active forum.
Pdsounds.org page that collects various sound files that belong to the public domain.
Assetstore.unity3d.com a huge collection of paid and free game items. The things you find here can be used not only in Unity!
bagfullofwrong.co.uk on this site we will find several packages with various things.
Gameart2d.com you will find a lot of good quality 2d graphics. Unfortunately, most are paid.
Dumbmanex.com a small collection of 2d graphics
Reinerstilesets.de quite a large collection of 2d and 3d graphics, textures and sounds. Unfortunately, their quality sometimes leaves a lot to be desired.
Glitchthegame.com a huge collection of gadgets! On the site there are links to GitHub, where there is a part of the collection.
Roencia.com Another collection of the rather low quality.
Lostgarden.com at this address are really nice to have a package of graphics.
Subtlepatterns.com a collection of textures.
openclipart.org a huge database of clipart.
Hasgraphics.com sets of 2d graphics and animations
freesound.org large base containing sounds
Blender-models.com noteworthy page with elements created in the blender. Note! Check your licenses for some restrictions.
7soul1.deviantart.com Graphics pack for RPG games
Game-icons.net large collection of various icons
www.soundfx.pl Polish website with free sound effects. All files can be downloaded without limits and registration.