A metasite is a website that functions as a directory to other websites.
https://www.composerdiversity.com
The Composer Diversity Database allows users to discover almost 4,000 composers from underrepresented groups. You can search by composer name, living or deceased, specifically for women or non-binary composers, common large and small ensemble genres, racial, ethnic, or cultural demographics, and by location (city, state, and country). Sponsored by the State University of New York (SUNY) at Fredonia.
https://www.archive-it.org/collections/4049
According to the site's description: "A curated collection of websites devoted to (and typically owned and operated by) individual contemporary composers. The primary curatorial goal is to preserve these historically important documents of the music and musicians of our time as a legacy to posterity. 'Contemporary' we define as living or recently deceased. 'Composers' we define as those who are working within, or are descending from, or are in some significant way connected to the Western traditions of concert music—composers who produce notated scores but inclusive also of those whose work embraces improvisation, collaborative composition, and other post-modern/post-classical creative practices. As there are many thousands of such composers active in the world today, we are emphasizing young, emerging Americans in the initial phases of this project."
https://pinboard.in/u:HarvardMusicLib/
Sponsored by the Loeb Music Library at Harvard University, a long list of Internet sites covering all aspects of music from acoustics to women in music.
http://vos.ucsb.edu/browse.asp?id=2722
Lists numerous sites arranged by time period.