Here's an oldie. It's a hat which made it into Team Fortress 2. At the time, the polygon and texture limits were a bit more severe than they are today, but I still like the achievement of getting accepted, so I thought I'd share this here.
For those who are not familiar with the concept; Team Fortress 2 is a team based (obviously) stylized shooter which came out all the way back in 2007. Valve, which at the time still created games, launched the Steam Workshop in 2011 on which artists were able to contribute items, such as hats, weapons and maps, which were available in game once they got approved by Valve. Here's my first contribution, the Barnstormer hat, created as the Hughes Improvement.
I'm talking only about the hat, the characters were created by Valve. Renders are done inside Team Fortress 2's Source engine.