@cloudrivera:
Let's see, we have:
The Captain
Cook
Navigator
Swordsman/Firstmate
Doctor
Musician
Shipwright( is that the word for Franky? lol)
Helmsman/sniper
Archaeologist
Since the basic roles are covered, the next crewmate or mates could be:
Child/Apprentice- Momo fits this role
Mentor- Jimbe (this is obviously already part of the crew but since he hasn't joined yet..)
Botanist- Sunny does have plants
Former Marine- this could be interesting as we can learn exactly how the marines work
Former Government Employee- like above, it could be interesting to learn how this institution works, no not a warlord
Gladiator- This could happen in Dressrosa *coughRebeccacough
Chemist- I don't think we've really seen this in One Piece yet, maybe Caesar Clown could be considered one but I think he's mostly a Scientist
Dancer- would work great with Brook
Bodyguard- Tank of the crew, would be interesting to see conflicts with Sanji over protecting the females lol, would actually fit with Sentomaru
Weapons Master- We see swordsmen everywhere, would like to see someone use a variety of weapons
Martial Artist- yeah Jimbe could be considered one but I wouldn't mind seeing other fighting styles in the one piece world
My point? I have no idea what Oda is going to do lol
Most of those are already covered unnofficially.
Botanist: Usopp and his Pop Greens.
Chemist: Usopp again, with his special ammunition. Chopper and his potions could also count.
Gladiator: Lucy.
Weapons Master: Franky. Flamethrowers, guns, flails, missiles, lasers…
Bodyguard: Franky is literally a tank. Invencible from the front and even has trademark shades.
Former Marine/Government Employer: Unnecessary. Robin is bound to have enough knowledge about the Marines and WG. Plus, this is Drake's main gimmick.
Mentor: Rayleigh already played this role.
Quartermaster: Nami.
Fisherman: Usopp.
Helmsman: Chopper and Franky.
Lookout: Zoro.
Martial Artist: Kung Fu Point Chopper.
Jinbe will probably fill the role of "Veteran". Beta Usopp was supposed to play this role after all.
Cabin Boy is a possible job, but I don't see Momo filling that role. A Priest could also work as those used to be common in ships during the Modern Age.