Explorendium (A Compendium)

There should be a compendium of all encountered mobs, to go along with all the obtained weapons and armor. A mob would get added to the compendium when you defeat one/it. I think it would be cool as sort of a collector thing that would help you feel more completed while adventuring. It could have all caves found or secrets explored as well, with a little X/100 or whatever going on there.