Jen_scripts is a GameMaker Language (GML) library designed for procedural terrain generation in GameMaker Studio 2. The library includes support for most common terrain generation techniques, including heightmaps, cellular automata, wandering paths, maze generation, flood-fill, and geometric shapes. Furthermore, terrain data can be stored, copied, and combined, allowing for easy integration of hand-crafted content into the procedurally generated level.
Jen_scripts is available as a local package on itchio: https://cloakedgames.itch.io/jen-scripts.
Documentation is available here: Google Docs