Here are some websites where you can download free vectors/patterns etc to use:

brushes
https://www.brusheezy.com/
http://www.brushlovers.com/
https://www.brushking.eu/
http://fbrushes.com/

textures
https://www.textures.com/ (small/medium images free)
https://freestocktextures.com/
http://www.wildtextures.com/
https://www.textureking.com/
http://texturelib.com/
http://www.texturemate.com/

vectors
https://www.vecteezy.com/
https://www.freevector.com/
https://www.vexels.com/
http://nl.vector.me/

mixed
http://all-free-download.com/
http://www.freepik.com/
https://www.stockio.com/
http://freedesignfile.com/category/free-vector/

I had no idea where else to post this