https://www.xda-developers.com/tag/wallpapers/ looks like a decent contender.
There's also an android app called STOKiE that has a large selection.
I'm not aware of anywhere that will categorically have every wallpaper from every device though.
Hope this helps!
As Apple, Signal, Element etc have stated. The hilarious thing is most of our politicians use WhatsApp. Why that's allowed I'll never understand but, given the fact this bill is even still around, I'm assuming the level of security/tech literacy at the home office is pretty fucking low.