I've done a few designs for és footwear over the years. Here's one called Mongo.
Every once in awhile I'll do work that never gets produced, here's an example. I was asked to do 5 shirts based on 5 different cities. I spent about 4 weeks on the project and when I was done, the marketing folks had decided in that time that they weren't interested in the "monster" thing that season. In any case, I still got paid but these designs ended up in Limbo.