These frontends are commonly used to bypass parental controls and content filters. They run on thousands of arbitrary, ever-changing domains , making manual custom rules impractical. No existing RethinkDNS blocklist covers them.
Each of the following projects maintains a public, machine-readable instance list that updates automatically as new instances are added by the community:
Redlib (Reddit) — raw.githubusercontent.com/redlib-org/redlib-instances/main/instances.md
Invidious (YouTube) — api.invidious.io/instances.json....
And so on for majority of the alternative frontends...
Parents, users with self-imposed restrictions, and MDM administrators would benefit a lot from this.