If you want to use them, why not give Linux Mint 22 Beta a spin? You can find the wallpapers in /usr/share/backgrounds/ if you want to copy them and take them to your preferred operating system.

Either way, you get to the backgrounds menu. Linux Mint comes with a lot of wallpapers to choose from, both the standard ones ...

Linux Mint 21.3 is going to be the last release ... Of course, there is a big collection of new wallpapers to choose from when you upgrade to Mint 21.3. These will be one of the main attractions ...