Most of my less-than-common consoles have been named already- Fairchild Channel F, Atari 7800, and such. I did just acquire a (working!) Mattel Microvision, which hasn't come up yet.
As it stands, there's only 2 rare-ish consoles I still want- a Vectrex and a Colecovision (I guess those aren't particularly rare.) Maybe a TurboExpress, but I'm not familiar enough with the T16 catalog to know if I'd really want to spend the money.