Some not-so-tiny games as cited in sibling comments. Also some web applications; I've been pushing some to production for 6 years now.

Other random uses:

- lua target for a pokemon game, probably for scripting (no word from devs, just saw the licences)

- a video player made by feds to catch pedocriminals a couple years ago

- livejasmin (warning: NSFW!) is using it for its frontend (via docler holding) on a top 50 website