I'd be a midget, who hides in hard-to-reach spaces in patrol (randomly, and not always available).
I would sell you insulting emotes with limited uses.
(rude gestures, sarcastic poses, etc).
I would accept unclaimed blue engrams as currency.
(one engram gets you one emote, with three uses).
My stock would have a relatively large pool, with a new emote every month.