I'm a long time pi-hole user and follow the subreddit and discourse regularly. You'll find many a pi-hole user with whitelists. The following are pretty common.

* https://discourse.pi-hole.net/t/commonly-whitelisted-domains...

* https://github.com/anudeepND/whitelist

I have ~2.2M domains blocked. There's just no way that I wouldn't have false positives in that big of a list.