I've bought several different ones brand new that were later discontinued, but some I wish I would have picked up "way back when" are, and not in any particular order:

Diamondback 4" .22LR
Mateba Auto Revolver (although I think they brought it back in Europe)

Pythons, Rohrbough, Dan Wessons (all three calibers), and some others were all bought new and then discontinued, so the above two are about it.