Modular Cellular Automata for Designer-Curated Procedural Tilemaps
A wordy title, but essentially: This system allows the creation of specific and complicated rules without any use of code to be dragged and dropped into a generator that will then run over them in sequence to create maps like the one below! This map has a few rules, starting with: Fill the map randomly at 45% air, 55% stone. Any stone that has less than 5 stone around it becomes air. and air that has less than 5 air around it becomes stone. at certain points, dig a tunnel downwards. Place bridge starts. extend bridges. Each of these rules is it's own module that can be duplicated, dragged and dropped in any order to change the generation, without any need to touch the code.
Here's another version, using some different rules!