Assassins - Hired killers including Cutthroats, Ninjas (from the Azagolian Empire), Thugs.Bards - Musicians with a talent for getting into trouble.
Bounty Hunters - People who hunt down wanted criminals for the reward money.
Clerics - Holy priests who worship specific gods (or possibly pays homage to multiple allied gods) and practice divine magic (miracles, healing magic, calling upon divine might using prayer). Clerics typically carry some kind of holy symbol which can also be used to drive away undead.
Commoners - Everything from farmers to innkeepers to merchants to miners.
Craftsmen - Everything from carpenters to stone masons to weaponsmiths.
Cultists - Zealous religious people devoted to worshipping a demon or demi-god or possibly even a dead god (ie. The Dead God Saraz). Cultists typically don't have any magical talent, but are often amateur warriors.
Druids - Wise people who worship nature and develop divine woodland magic.
Fighters - Warriors of every type including Archers, Barbarians, Berserkers, Cavaliers, Cossacks, Crossbowmen, Knights, Mercenaries, Myrmidons, Soldiers, Swashbucklers, Town Guards.
Monks - People who devote themselves to meditation and martial arts, often using martial arts styles from the Azagolian Empire (a cross between Mongolia and Korea).
Mystics - Magic users who derive their powers from magical objects: Crystal Orbs, Staffs, Wands, etc.
Nobles - People born into nobility or royalty (but not necessarily wealth).
Paladins - Holy Knights in the service of Metrequia.
Rangers - Rangers are woodsmen who are skilled with ranged weapons. Some rangers even have druidic magic.
Sorcerers - Magic users with innate magical powers they are born with.
Thieves - Brigands, Cat Burglars, Fences, Horse Thieves, Kidnappers, Pirates, Rascals, Rogues, Scoundrels.
Wizards - Magic users whom cast their spells via spellbooks including Abjurers, Aquamancer, Chronomancers, Conjurors, Diviners, Enchanters/Enchantresses, Evokers, Necromancers, Pyromancers, Transmuters.
Plus there is always the option of creating your own special kind of adventurer...
Arcane Cavaliers - A wizard who specializes in horse combat and casting spells from horseback.
Archaic Korovian Knights - One of a handful of ancient knights who were trapped in para-elemental ice and later thawed out and still alive. They speak Ancient Korovian and are more traditional in their thinking and thus are "fish out of water", but can still hold their own in a fight.Blizzards - Wizards who have undergone a magical transformation that turns their skin blue and are now immune to cold. They often specialize in ice magic.
Ice Knights - Knights who worship the goddess Karolina the Cold or a similar ice god.
Ironskin - Minotaurs who are a cross between paladins and monks and develop extra hard skin.
Taltos - Similar to gypsies, Taltos are tribal nomads who specialize in killing undead and have spirit guardians who follow them around since birth. For more details see the short story "One to be Reckoned With" by Charles Moffat. (The term Taltos comes from Hungarian folklore.)
Wolfkin - People descended from the Wolfkin tribe who have bonded with wolves and can communicate with wolves either mentally or verbally (the bond grows stronger with age).
