How do I add My Presets of a certain type say UnityEngine.Material, if that type is not listed?

It's not listed in the Presets Manager when you click the Add Default Preset... There's nothing relating to Material..nothing. And i tried Adding the Skin Mesh Renderer but that doesn't work. When i drag my Presets onto the slot, they're not accepted because it's just not the type they belong to. My Presets I saved out of the many Materiials of each body part of my Character. well just the eye material parts in my case. like i called them FIXEyelashes, FIXIrises, FIXSclera, FIXCornea, etc. and i know they're of type UnityEngine.Material cause when i click on one of them in my assets folder and look at the inspector it says Preset type UnityEngine.Material.....And like i said that preset type is no where to be found in my PRESET Manager's Add Default Preset button thing.

Do i have to add some classes packages to my Unity, i just installed Unity 2020.2.5 last week, i dont know if i need to installl extra classes or something in order for these PRESET things to appear. Please help