I've got numerous interests, and I always find something useful on either Google,
Bing, or Youtube. The main interest of videokarma.org is plentiful on Youtube.

As to classical music, try arkivmusic.com, or as a last resort, the
old Usenet group rec.music.classical.recordings, which is still active. For medieval genealogy the gold standard is still soc.genealogy.medieval.

Sometimes. I like roadside architecture and retail history and other kinds of things, and sometimes I Google places or things and there is nothing. More often than not, I find some interesting information.