It's impossible to say which ones are you missing without knowing which ones you did already... My wild guess is some maps from the merchant in Thula or some puzzle.
i didn't have the 3 from that merchant yet. but seems like i'm still missing one. here is the list of all the maps i have so far.
Neatly folded,
slimy,
slavers,
ogre's,
ancient,
old,
dusty,
grotto,
charred,
faded,
map with perfume,
crumbled,
forgotten,
hunter's,
alchemist's,
maggie's,
rolled up map,
ali1,2 and 3