Something new. quad9.net is doing this, and it appears both very fast and very worthwhile. Same feature space as 1.1.1.1 and 8.8.8.8, adding bad-actor blacklisting in both IPv6 and IPv4 in its default. This is the first real IPv6-enabled security service of which I am aware, I have been watching and waiting for this for quite a while.
Uses primary 9.9.9.9, secondary 149.112.112.112.
There are other features too.