Free, uncensored, from northern europe (Denmark): https://blog.censurfridns.dk/
honorable mention: Digitale Gesellschaft (Switzerland): https://www.digitale-gesellschaft.ch/dns/
As for DNS Benchmarking: I used a Shell Script to check the performance of my pi hole. I got that from github, just look for "dns benchmark github" and you'll find tons of script in all languages people wrote.
Edit: got two more:
Dns.watch (Germany): https://dns.watch/
Digital Courage (Germany): https://digitalcourage.de/support/zensurfreier-dns-server