SIDN Labs DNS Workbench
https://workbench.sidnlabs.nl/DNS | DNSSEC
The DNS workbench is a testbed which allows experimentation how different authoritative DNS servers answer to queries.
It covers five open source authoritative servers, namely Bind9, Knot, NSD4, PowerDNS, and Yadifa. The workbench contains zones to test the support for many different resource record (RR) types, DNSSEC validation and how invalid zones are managed, delegations, zone transfers, and potentially more.