ok KI, time to ad an item to the drop list. I am farming for key limes in khrysalis, food cave, darksun goliaths. the list says they only drop key limes for seeds. I have received fiery boom shroom from them, not key lime.
If you go to castle tours and visit an acropolis the minotaur frequently gives key limes and key limes frequently re-seed. However, if you are hoping for some sort of amazing stuff- key limes are not the plant to get the best they give is rank 3 pet snacks. Also, these are the battle drop sources - http://www.wizard101central.com/wiki/House:Key_Limes