Cloudflare recently announced a new free, privacy orientated DNS resolution service (1.1.1.1). This looks like an interesting alternative to Google DNS (8.8.8.8) and Cisco's Opendns (208.67.222.222) services.
https://blog.cloudflare.com/announcing-1111/
The support for DNS-over-HTTPS looks particularly interesting although I haven't had chance to look at how it can be usefully implemented in a home environment. This may provide a Pi orientated solution...
https://scotthelme.co.uk/securing-dns-across-all-of-my-devices-with-pihole-dns-over-https-1-1-1-1/