Weapon Skin with new animations, For example:

-Trident skin for throwing knifes, works the same but you throw a trident like a spear, stab like the knife and an over head stab like the knife very similar but completely different skin.
-2h sword same as normal sword but you hold it with 2 hands

Sadly weapons are hard to change up to much unless you go down valorant type skins for them.