dnsx is a fast and multi-purpose DNS toolkit allow to run multiple DNS queries of your choice with a list of user-supplied resolvers.
MassDNS wrapper written in go to enumerate valid subdomains using active bruteforce as well as resolve subdomains with wildcard filtering and easy input-output support.
Lists of public DNSCrypt / DoH DNS servers and DNS relays - Actively maintained since 2011.
A high-performance, recursive DNS resolver server with DNSSEC support, focused on preserving privacy.
Public DNS resolver that protects you from ad trackers
DNS stub resolver, proxy and router with support for DoT, DoH, DoQ, and DTLS