The marbles shown in this thread are hand painted porcelain "chinas" made in Germany.
As for the reference sites you mention . . .
Robert Block's site: https://www.marblecollecting.com/
Joe Marbles site is here, literally: https://marbleconnection.com/joemarbles/
Alan's site is now curated: https://buymarbles.com/marblealanhome.html
And you are currently on a site that, no doubt, "chronicles entire lifetimes of knowledge and detail. And tons of reference photos".
Welcome back to marbles!
🙂