Note, this list is restricted to mods in historical setting, meaning Third Age, Warhammer and Westeros will not be on this list, especially because these are some of the most popular mods in Medieval 2 and many of you have already heard of them.
Because I am bored and have seen lots of people asking about the wonderful world of Medieval 2 mods, I have taken it upon myself to help the newbies separate the wheat from the chaff.