It is no small fact that you can find stuff from just about any fandom on Etsy.com. Ponies, anime, Doctor Who, etc. And for the most part the owners of these IPs look the other way on things being sold through this massive market. But there is a key word here, mostly. As of this week Valve has submitted a cease and desist order to Etsy requesting all Valve merchandise be removed. That means as of now you can no longer find Portal patches, TF 2 trays, or Half Life hangers (no clue if two of those things actually existed).
I will be honest that I am a little surprised that this does not happen more often. With no quality control anything could go out with a companies brand on it, for good oor bad. But given the rarity of events like this it makes you wonder, is something is going down at the house Gabe built?