Is there a way to allow selective access to certain contacts for other apps? Some messaging apps sync your phonebook with their server to find other users of the app. Is there a way to block access to some contacts and allow access to others?
I don’t think this would be possible as a standalone app. This would have to be a feature in a ROM (eg LineageOS), or maybe in Xposed.
XPrivacy but it doesn’t work well since Marshmallow.
There are no such apps on the market as I know. You can just use a phone’s or app’s blacklist to block unwanted contacts