For example (just as rough proof of concept)
Research articles: Pretty much any academic library website for published stuff, arxiv.org for white papers in computer science and math, pubmed for biosciences
audio equipment: gearspace.com
Encyclopedia: Wikipedia
Thesaurus: Wordhippo.com
The idea is to avoid needing to visit a search engine. Might be a high idea.
I’ve signed up for an account on curlie.org which seems to be the main existing option. Looks like you can apply to be an editor of a particular collection. Looks like they need more people. I’m going to get my bearings then might sign up to contribute as an editor for some topics.