Ok so here is a quick run-down of my villager tier list.

THIS IS MY OPINION!!
feel free to refute and give your reasoning in the comment's!

No tier -
  villager defualt -
    can become any of the following, so it really can't be slotted within the rest...

F (Fishy) -
  Fisherman -
really only good for getting emeralds from, beyond that- I see nothing useful about this guy beyond the sale of an     enchanted fishing pole...

E (Ew) -
  Leatherworker -
I would have put him with the Fisherman, however I feel like the saddle trade can be useful,
beyond that this guy can only sell sub-par armor, which can be used to some effect at the beginning however later on is pretty much useless..

D (Dasterly) -
  Stone mason -
In my opinion the stone mason is a great way to sell off stone you get from mining, which is pretty much the only use he     has- he doesn't have great trade's but he does come in handy when you need a little extra emeralds. 

B (Bakers man) -
  Butcher -
In my opinion, he is a really good way to get money ,"emeralds", in the late game- him being able to buy sweat-berry is     pretty sweat along with being able to buy blocks of kelp, the only issue is that these are late game trades but personally     I think its worth it later on.
  Cleric -
The only reason the Cleric is up here is because he will buy rotten flesh, and will sell you bottles o' enchanting...
yep... everything else is pretty meh..
I guess selling nether warts is okay... but it really isn't a good way of gaining emeralds...
  Shepherd -
The ability to sell dye can be pretty useful, and if you cure a zombie villager into a shepherd, it becomes pretty          exploitable! that's it really...
  Cartographer -
Maps! really good stuff...

A (AND THIS IS TO GO EVEN FURTHER BEYOND!!) -
  Armorer -
Really great way to get armor, and the ability to get enchanted armor in the late game- makes these guy's a pretty solid "a" tier.. they will also buy buckets of lava.... wait... maybe that's not the best use of them...
  Weapon-smith -
pretty much, you can't go wrong with one- however the can be pretty low tier at times, but at there best its pretty good to     have them around.
  Fletcher -
sticks and stone can break your bones, but the Fletcher will give you emeralds for them- and then later on you can get     enchanted bows and cross-bows.
sign me up!
- the only reason he isn't in S tier is because there is a villager is way more effective at getting you emeralds..

S ( SUpER DuPEr )
  Farmer -
on top of being one of the most effective ways of getting emeralds, they can be used to auto-mate farming which is one     of the best things about them!!
If your village doesn't have one, are you even in a effective village?
  tool-smith -
the fact is, getting a diamond pick-axe with and enchantment is almost always a great deal, so what is the downside-
besides not being able to give you emeralds, I'm at a loss on why you wouldn't get one?
  Librarian -
Enchanted books...
pretty much if you want any enchantment just use these guys, and they will hook you up!

(( GOKU Tier )) -
  Green God Miggee -
this is shaggy's older brother, and is basically the most powerful villager....

 If you are still reading this, thanks for allowing me to indulge you with this amazing TierList, and if you do not agree with what i said, tell me in the comments, or make you own tier list!!
this will conclude my tier list!!