Black, Clinchers, Decent weight, I'd say you look for wheels with Amborsio Elite 19 rims. The definitely came in anodized black as I had a wheelset with them back in the 80's. There were a lot of black anodized clincher rims from Matrix too from the mid 80's that were very good quality and not heavy.
If you want to try tubulars, maybe try out sheels with Wolber Profil 20 rims. not quite black but very dark in color and looks like black in most of my pics. Very strong and stiff early aero profile design. I recommend it as the rims can usually be found at eBay for not so much money compared to other tubular rims.

Chombi