I use Mullvad’s DoH.

NextDNS

Unbound running locally

Is Quan9 still a thing? Always liked them but I haven’t had the means to set up anything reliable in a while, service-wise (long story). They’re pretty solid last I knew.

I use the one provided by my vpn - this year that is Proton. Next year, Mullvad.

I've sometimes used NextDNS.

https://mullvad.net/en/help/dns-over-https-and-dns-over-tls

I've been using libredns.

It's fine.

Your own name resolver.