So I got a bunch of mods from Grimrock that I downloaded from the Nexus, mainly items and tilesets for the editor such as the Southern Temple and Mine of Malan Vael tilesets.
The problem is they aren't showing up at all when I open up the editor. I even manually installed the mods by copying them all to the mod assets folder and adding their lines from the readme into the init.lua file (which originally wasn't in it's proper location for some reason). However even after making sure the lua had all the mod's listed and they were in their correct places, opening up the editor shown nothing new.
If it means anything I also copied the Grimrock folder to a new HDD after installing a while ago but left the folder in My Documents where is was. I've also downloaded custom dungeons from the Workshop and they worked fine.