The production of tools and parts. Often paired with other skills. In the case of working with multiple materials, multiple skills will be necessary.

By Metals – Typically paired with a complimenting Smithing.
Tool Crafting (Gold)
Tool Crafting (Silver)
Tool Crafting (Copper)
Tool Crafting (Bronze)
Tool Crafting (Brass)
Tool Crafting (Iron)
Tool Crafting (Steel)

By Gemstones – Typically paired with a complimenting Carving for the gemstone.
Tool Crafting (Diamond)
Tool Crafting (Ruby)
Tool Crafting (Emerald)

By Animal Materials – Typically paired with a complimenting skill for the material.
Tool Crafting (Fish Scales)
Tool Crafting (Leather)
Tool Crafting (Bone)
Tool Crafting (Hair)

By Plant Materials – Typically paired with a complimenting skill for the material.
Tool Crafting (Wood)

By Other Materials – Typically paired with a complimenting skill for the material.
Tool Crafting (Glass)

More subsets will be as materials are discovered and introduced into the lore.