I found another grab bag treasure. I ended up with a 16x16 stud clear(ish) base plate. A quick look at bricklink gave me a no items found message. I'd like to know which set(s) this piece can be found in as I have grand plans in mind.
Any of these three sets
6162-1 A World of LEGO Mosaic 4 in 1
6163-1 A World of LEGO Mosaic 9 in 1
852676 Travel Game - Multi Game Pack 9-in-1)
Bricklink hint: just search for a size, like "16 x 16". "3x3 plate" is fun too.