Vendor lineage
Quad9 - a public resolver that blocks by default
Swiss-based public recursive resolver that refuses to answer for known-malicious domains.
Quad9 operates a public recursive DNS resolver from Switzerland, and its distinguishing choice is that blocking is the default rather than an option: queries for domains on its threat feeds return no answer.
That makes it the clearest working example of DNS as a security control available to anybody, without an appliance or a subscription. Pointing a resolver at it applies a threat feed to every device on the network, including the ones that cannot run an agent.
The Swiss jurisdiction is part of the design rather than a detail of incorporation, because the question a public resolver has to answer is what happens to the query log. A resolver's privacy posture is a legal position as much as a technical one, and it is the property worth comparing between providers.