Source (required if based on other people's work): https://github.com/dorianpro/kali-linux-wallpapers
Wallpapers with simple abstract design containing the Kali Linux* Logo
This set of wallpapers is dedicated to Kali Linux users and developers.
I'm going to update regularly. They all done using GIMP and other GNU/Linux/FOSS.
*Kali Linux™ is a trademark of Offensive Security.