You will find a list of every single enemy that drops an item in this section of the guide. Almost every single enemy in the game will drop an item upon defeating them in combat. As you will find out, there are numerous ways in which you can defeat enemies, such as finishing them off with a fire skill, which will reward you with a different item sometimes. These materials can be sold to the Magic Consortium NPC to purchase new Command and Support Spritnites that can be equipped to your characters.
For those enemies not listed, that will be because they do not drop anything. One such example is the Reaper NPC that you fight, as he doesn't drop a single item from any of the fights against him. Also, while the normal enemies will have a plethora of drops (up to a maximum of 12 different ones), the bosses don't always have that many drops (they might only have one or two). One last thing pertains to the Normal and Rare drops, as the normal enemies will always drop one of the two, but a single enemy will never yield both at once.