Quad9 is one of the few globally active public DNS resolver and is operated by a Swiss non-profit company. Quad9 operates DNS servers in more than 200 locations around the world and has a focus on data security, encryption and privacy.

Quad9 is currently involved in a legal dispute with Sony Music about whether websites that infringe copyright can be excluded from resolver. You can read more about the dispute on Wikipedia.

DNS.WATCH is a public DNS resolver from Germany with a focus on privacy (no logging) and security.

DNS.SB is a public DNS resolver from Germany with a focus on privacy (no logging) and security. The software is open source and they support DNSSEC, DNS over TLS and DNS over HTTPS.

The non-profit organization Foundation for Applied Privacy offers a public DNS resolver that offers DNS-over-HTTPS and DNS-over-TLS. The servers are located in Austria and Germany.

The Swedish VPN company Mullvad offers a free public DNS resolver. It supports DNS over HTTPS and DNS over TLS. They also offer a resolver with ad protection and one without. The list of blocked domains for the DNS protection is maintained on GitHub.

UncensoredDNS is a public DNS resolver from Denmark. The support DNS over TLS and DNS over HTTPS.

The restena DNS resolver is a service of the Luxembourg Restena Foundation. The support DNS over TLS and DNS over HTTPS.

Digitalcourage is a non-profit organization from Germany that operates a public DNS resolver. The resolver is hosted in Germany and supports DNS-over-TLS. The site that explains the service is only available in German language.

The German non-profit Artikel10 e.V. is operating a public DNS resolver which supports DNS-over-HTTPS and DNS-over-TLS.