Necroposting, but I was looking in to this very issue and found this:
or
gg6zxtreajiijztyy5g6bt5o6l3qu32nrg7eulyemlhxwwl6enk6ghad.onion/RightToPrivacy/WiPri/
I am hesitant to use it without it being more widely used (or audited), or (god forbid) understanding how it works myself. But perhaps it’s a place for someone else to start.