Custom Machinery is a Minecraft Forge mod currently developed for Minecraft 1.21
This mod can be used to create custom machines and recipes for them.
You can find some working examples of Custom Machines here
You can download the full test datapack here (It can take a few seconds to complete the files zipping) Just download the zip and extract it in World/datapacks/test_datapack/ (you can replace "test_datapack" with what you want)
You can download a test resourcepack here This will give a custom model to the "Stone generator" machine present in the test resourcepack.
Download this mod on CurseForge
This mod is under the GNU LESSER GENERAL PUBLIC LICENSE
Btw you are free to use this mod in any modpack.