Dungeon Starters are for those times when you want to just sit down and start a game right right away. Just a couple pages long, Dungeon Starters provide a unified flavor. Among other things, they include some simple details, questions, impressions, custom moves, items and services, spells and monsters. Sometimes there is even a map or visual image or two.
I really enjoyed "The Paths of Ateşkazé" by Jeremy Strandberg, in Perilous Almanacs. Two of my players (a married couple) are cavers, and they absolutely loved the descriptions of cave passages— they said it felt very realistic, and a couple times they had to tell us a story out of character about their caving!