For our friend Adam's birthday last week we (my other friends Beth, Heather, and Ron) set out to make Avengers Cupcakes. And I looked everywhere and I couldn't find any kind of cake/cupcake toppers of the Avengers. At one time Marvel did make them but they are long discontinued.
So with a little work I made my own
I found a great sticker book at Michael's and attached the stickers to white poster board. Then just cut out the characters. And with a hot glue gun, I glued tooth picks to them. In the end I thought they came out great and our friend Adam loved them so much he ended up keeping them.