Creative Commons allows free use of web content to be shared. Legal permissions are granted, but they are not all the same. Some are offered for non-commercial use only, while others are not restricted at all. Specifically, creative commons is a set of licenses
You can look here for some of last years top Creative Commons content. You can also use bing.com to do an image search for creative commons images. Enter a search term and then select creative commons from the licensing tab.
My favorite open source project is lichess a totally free online chess server. It’s not just free it’s easily the best. It’s released under an MIT license and you can view all of the source code on GITHUB if you’d like. (GITHUB is also awesome, and if you like computer coding at all and don’t know what it is, it will blow your mind!)