Grab bag baby griffins or maybe even fledglings seem more likely to me.
Grab bag fledglings!? *brain explodes*
(I don’t expect GB fledglings to ever be made, but the idea is amazing.)
I seem to recall reading something about GB baby poads, and the design seems simple enough to paint quickly, so that makes sense. I think small flap cats might work too, and they would certainly be very popular. Aside from the baby pegasus, I can’t think of any other sculpt that’s small and relatively simple enough to work as a grab bag piece.