This repo is a quick example on how to set up custom sign types on 1.18 fabric.
Created by nyuppo with help from the fabric discord server: https://discord.gg/v6v4pMv
This repo makes use of access wideners to fix an issue that prevents modded sign drops. It is assumed that you know how to enable access wideners for your mod, but an explanation can be found here if needed.
Note that, while not included in this repo, you still need a model and blockstate for your sign block to give it break particles.