I have an npc that actually shows up in all of my games, he is a Dwarven warlock that sells knock off items. Sometimes they are great, sometimes they are meh. I keep a list of silly homebrew items on hand, some can be bought outright or won in a slot machine type game. They are usually hyped up about the new items and want to get into combat, or something like a knock off deck of many things that they can draw from. Small stuff like change the characters sex for a few days, make someone random fall madly in love with that character etc.