E.g. to add the silver category... so that you can forge silver weapons from there... not from misc category?

From what i know, what catagory an item is placed under is related to the keyword that tells what material type the item is (Iron, steel, glass, etc), so it may be possible. not sure how though.

The crafting categories are hardcoded.

It may be possible to change via SKSE plugin, but I really have no idea.

It should be a simple matter of creating a Constructable Object (recipe) for a silver sword that is set up to use the CraftingSmithingForge workbench setting. Then supply the components required for it like any other weapon.

You'd just need to keep in mind that in the vanilla game there's no specific perk for silver smithing. It just assumes everyone knows how since Bethesda only intended for silver to be used for making jewelry.

EDIT: I see what you mean here. I wonder if that could be messed with in the UI itself?

I wish I knew how to do that.

I 'd like to know too , especially if it coul dbe possible to add a new special category under a new type of unique forge?

I found no tutorials on how do use SKSE online, does anyone know how to do this?