There's no need for an extension; plenty of websites are part of webrings or feature blogrolls. I'm in the process of adding one to mine.

Throw in some microformats2 and/or schema.org structured data and you're good to go.

Certain search engines specialize in this type of manually-curated content; I listed some in the "non-generalist search" section of my collection of indexing search engines: https://seirdy.one/2021/03/10/search-engines-with-own-indexe...