The stuff that shows up when you search for "Homestuck" on Amazon.

Gray face paint, in case you want to cosplay as a troll.

A red cane, in case you want to cosplay as Terezi, specifically.

3D glasses, in case you want to cosplay as Sollux, specifically.

Detective Pony (Pony Pals #17), in case you are intrigued by the deathless prose sampled here.

Never Trust a Troll! #18 (Dragon Slayers' Academy), I guess because Amazon's search algorithm has basically attained sentience at this point.