Here's a list of the leathers MJ has used for his collections. There may be more, so please feel free to add to this list.
Drummed/Goat Leather
Calf Leather
Tumbled Calf
Soft Calf
Calf & Cow (70% Calf/30% Cow)
Vegetable Tanned
Quilted
-Matte
-Icy
-Mouflon (another word for metallic, I think)
Metallic
Suede
Spazzolatto
Patent
Exotics (in limited quantities)
-Crocodile
-Alligator
-Python
-Ostrich
-Lizard