Adblock tests

https://d3ward.github.io/toolz/adblock
https://adblock-tester.com
https://test.adminforge.de/adblock.html
https://blockads.fivefilters.org

Browser/Ad tracking tests

https://coveryourtracks.eff.org

Bufferbloat rating tests

https://www.waveform.com/tools/bufferbloat

Connection benchmark tests

https://speedtest.net
https://www.fast.com

DNS (generic) tests

https://www.dnsleaktest.com
https://www.perfect-privacy.com/en/tests/dns-leaktest
https://one.one.one.one/help

DNSSEC tests

https://dnssec.vs.uni-due.de
https://0skar.cz/dns/en
https://rootcanary.org/test.html


DNS (speed) tests

https://dnsspeedtest.online/

External Port tests

https://canyouseeme.org/


Multitest sites

https://ping.eu
https://www.yougetsignal.com