COMC lists these rounded corner cards (I can't tell on the foil; not good at that) as part of an insert set. Basically, there is the 2011 Topps Attax set, and then this insert, Ticket to Toppstown. I don't see a checklist here.
I'm not 100% sure on this, but that's what I found, anyway. Seems weird to me to have an insert set, then a separate base set with it's own inserts all covering the same subject matter, but that's Topps for ya...
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.