Yeah, it disappeared a little while ago - real shame. People used to make these websites and encourage folks to upload their own photos to a CC-0 database for making textures. You used to be able to find loads just with a simple Google search like "photos for texturing" - but they've gotten harder to find, with most going down over the last few years. I guess they were passion projects, and either the passion dried up or the funds did. Those old websites were a goldmine, RIP to the real ones.
I can't recommend anything similar, but you can check archive.org using the search terms subject:"image library" and subject:"photo cd" to find CD-Roms full of old images - but beware, rights are often an issue. Also here on Itch Screaming Brain Studios makes the best retro textures.