DNS
Quad9: 9.9.9.9 & 149.112.112.112 Quad9 website
Quad9 has free public DNS servers that protect your computer and other devices from cyber threats by immediately and automatically blocking access to unsafe websites. One thing I appreciated while researching this company is that it works without storing your personal data; their website clearly states that when you use Quad9, „no data containing your IP address is ever logged.“
Primary DNS: 9.9.9.9 Secondary DNS: 149.112.112.112
There are also Quad 9 IPv6 DNS servers:
Primary DNS: 2620:fe::fe Secondary DNS: 2620:fe::9
Quad9 doesn't filter content—only domains that are phishing or contain malware will be blocked. There's also has an unsecured IPv4 public DNS (i.e., no malware blocking) at 9.9.9.10 (2620:fe::10 for IPv6). Quad9 also supports DoH.
Veel DNS
AdGuard DNS: 94.140.14.14 & 94.140.15.15 AdGuard DNS website
AdGuard DNS has two sets of DNS servers that block ads in games, videos, apps, and web pages. I used these „Default“ servers for several months to block ads and trackers, and I was pleased with its performance, despite ads slipping through at times:
Primary DNS: 94.140.14.14 Secondary DNS: 94.140.15.15
IPv6 is supported, too:
Primary DNS: 2a10:50c0::ad1:ff Secondary DNS: 2a10:50c0::ad2:ff
There are also „Family protection“ servers (94.140.14.15 and 2a10:50c0::bad1:ff) that block adult content, plus everything included in the „Default“ servers. Non-filtering servers are available if you're not interested in blocking anything: 94.140.14.140 and 2a10:50c0::1:ff. These servers are also available as DNS over HTTPS, TLS, and QUIC, as well as DNSCrypt. Compared to paid AdGuard DNS plans, free users have zero customer support and limited monthly requests, device access, and servers.