The Gridmapper algorithm for Text Mapper to generate small dungeons was based on the blog post The Nine Forms of the Five Room Dungeon, by Matthew J. Neagley, which I then extended to 7-room dungeons, and then I added the combination of the two, which led to 10 (5+5), 12 (5+7), and 14 (7+7) room dungeons. It worked surprisingly well, see 2019-10-09 Ten random dungeons generated, and 2019-08-23 Gridmapper inside Text Mapper. It definitely worked better than the failed Megadungeon project I was working on a long time ago. Reload it a few times until you more than just one level and then click on the last image to open it in Gridmapper.
A few days ago I started wondering whether I could scale that up… and it turns out that I can!
Here’s an example with 200 rooms. It definitely needs fewer entrances – and the latest version of Text Mapper does that, of course. See 200 rooms.