I just use one of the defaults. Wallpaper sites are mostly BS and sketchy and I can't be bothered to search for them mostly. If I can see my desktop wallpaper I'm not doing anything or just booted up. Tl;dr I'm too old to care. No offense to anyone who has rad wallpaper Edit: sometimes I queue my saved images as random bg, but I've forgotten how to do that again and I don't care