The Isometric Dungeon Generator is exactly what the name states. With this very customizable generator, you can have random dungeon layouts for your isometric game. In the demo you will generate a dungeon and be able to freely move around to see the layout or toggle the player view and move about your dungeon.
Feel free to contact me on via email or reddit, /u/nothingalike, if you need help.
Update 6/7/2017: ok im a bit surprised on how many people have downloaded this. thank you for the views and checking out the code. Heres the source code https://github.com/nothingalike/TopDownMapGenerator Looking to getting back into game dev utilities but probably moving to GM2
Update 8/27/2018: New Generator for GMS:2 https://marketplace.yoyogames.com/assets/7302/lovepunk-dungeon-generator