https://en.wikipedia.org/wiki/Alternative_DNS_root effectively an alternative to ICANN, which provides its own nameservers, to resolve TLDs to IP addresses.
- as of now, requires user manually changing their DNS settings in their network settings in order to hit the name servers of the alternative root because ICANN does not and explicitly does not want to support these alternative roots as argued in RFC 2826
One popular one is OpenNIC, which supports alternative top-level domains like .geek, .null, and more.