100's only drop from the "Big bosses", Conquerer Bagkodek, Di'Dha Adamantking(or w/e), and the Yagudo that looks like Tee Xicu with the 4 Elementals.

Either way, Its actually more beneficial as a whole to spread people across unions, Any union with ~7-8 People could hit the 10 item cap (and then stuff gets pushed out), especially in long battles. So having people spread across unions introduces more items as a whole!