Classes

Barbarian Few in number in the Known World, barbarians can be found primarily in three locations. The Northern Reaches are known for their berserkers, personal guard of the jarls and shock troopers in combat. The totem warriors of the Ethengar steppes and Atruaghin clans follow their shaman and embrace the teaching of the spirit animals. The wild savages of the Broken Lands sport large numbers of barbarians of the berserker variety.
Outside the wild north and the untamed steppes and the Atruaghin plateau, barbarians are rare if not unheard of in human or demihuman lands. It has been rumored in the unknown lands of Karameikos there might be savage men that fight with unbridled rage, and there are tales of fierce Makai warriors in the Ierendi isles, but these are often just rumors. The tribes of the Hinterlands in Thyatis have multitudes of barbarians, but they are loathe to leave the war being waged upon their homeland. In the more civilized lands like Darokin or Minrothad the barbarian is unknown and wouldn't fit in the urban landscape. Glantri is similar, except for the warriors of Crownguard, who's gallowglass champions through themselves at the enemy with a fury. The demihumans of Mystara tend to avoid throwing themselves into a rage, an thus the class is unknown for the most part in the Shires, Alfheim or Rockhome.
Bard There is not a nation in the land that does not have its share of bards. Bards are typically welcomed at all levels of society, from the bawdiest pubs to private audiences with kings and emperors. Bards of both colleges are equally accepted, as long as they can bring entertainment to the masses and the nobles as well.
The one difference between bards is the cultures have two varying tastes. The Northmen, Ylari and Dwarves prefer tales of history and legend over simple song and dance. A skald performing in Vestland had best know the jarl's ancestors back at least five generations to impress. In other lands like Darokin or Karameikos the bard is more an entertainer. Knowing Grand Duke Stefan's family tree is nice, but knowing the latest songs and poems will get you further.
Cleric There is no land in the Known World that does not have those spreading the word of the Immortals. They may not be accepted or even allowed, but clerics will defy man before they defy the Immortals. In the lands of Ylaruam and the Shadow Elves clerics hold enormous power, in Glantri they are put to death when found. Most other countries keep a balance between the clergy and state power.
Several special types of clerics exist in certain lands, other nations follow druids for their religion however. The Dwarves of Rockhome follow Kagyar who gives them greater resistance to magic at the expense of power over undead. The shaman of the Shadow Elves follow the mysterious immortal Rafiel, gathering sacred stones when possible. Hin Masters are esteemed by the little folk for their wisdom. Farmers more than clerics, they protect the Shires under the guidance of their pantheon. Druid Found in almost every country in the land, druids are either viewed as sacred holy men to be obeyed by all, or unknowable loners best left to their own devices. In nations tied closely to the land, like Ethengar and Alfheim druids are the population's clergy, replacing clerics. The Northern Reaches the druid is respected and feared all at once. Only in Glantri is the druid hunted down, viewed with the same hate reserved for clerics. Though the dwarves have few druids of their own, above ground they well human druids to tend the lands they reside under.
Both main types of druids are common, but there are two druids are unique to Mystara. The Dervish is found only in Ylaruam, a known wise man that can commune with the desert. The Sand Druid as the Dervish is also known, can change his shape like other druids, but he also can become a whirlwind of sand or walk through the hottest desert as it were a cool spring day. Spirit Shaman are the holy men of Ethengar. Touched by a animal spirit, their mastery of the spirit world is unrivaled. While they are revered on the steppes, their highly eccentric behavior marks them as foreigners anywhere else in the world.
Fighter The ubiquitous fighter is found in every country in the Known World. Any one who can pick up a sword has a chance at becoming a great warrior. Fighters are held in esteem over other classes in the Empire of Thyatis, but kept from power in Alphatia and Glantri. Many other lands revere personal strength in arms such as Ylaruam or Ethengar, while more merchant minded nations like Darokin or Minrothad see them as guards more than champions.
Of the archetypes for fighter both the champion and battle master are well represented across all the lands. The eldritch knight however is restricted to elves and the humans they train in Thyatis. Elves are highly magical, and their warriors take the Eldritch Knight archetype over the others almost exclusively. The Vyalia elves of Karameikos and Thyatis will train humans in their ways, but Eldritch Knights trained this way substitute abjuration spells for illusion.
Monk The mystics of Ochalea in the Thyatian empire are known for their unarmed warriors. Mystics of Ochalea follow the Way of the Open Hand exclusively. Mystics are unknown outside the island nation, for the class and people of Ochalea are almost unheard of outside of Thyatis.
Because of the rigid social structure on the island though, many women leave the island to become adventurers. Many mystics found outside Thyatis itself are women, along with male mystics with a sense of wanderlust. Mystics are found in most parts of Thyatis except the xenophobic Hattias. Several emperors were fond of their fighting styles. Demihuman mystics are extremely rare, having to learn the art from wandering mystics, but they aren't unheard of.
Paladin Where there is evil, there will be paladins. The crusaders find themselves in every land in the Known World, even where they are not allowed. Many countries have entire organizations either devoted to them or heavily supporting paladins, from Karameikos Order of the Griffon to the Shires' adherents of the High Heroes. In lands like Glantri the paladins have to weigh the nation's hatred of all things divine against their oaths to uphold justice.
The various archetypes of paladins are scattered through out Mystara. While those under the Oath of Devotion are the most common, in the elven and hin lands the Oath of the Ancients are more frequent. The more martial minded nations like Ethengar and Thyatis have many that undertake the Oath of Vengeance, though no region has a specific type of paladin exclusively.
Ranger Where there is wilderness, there will be rangers. The nomadic nature of many of them make them more loyal to a specific forest or a desert than a single country. Every race makes us of them, especially the elves and gnomes of Karameikos. Even the pastoral Hin and subterranean dwarves make extensive use of rangers.
Mystaran rangers are more varied than one would expect. Ylaruam has numerous desert dwelling guides that can survive for weeks in a land that would kill most in days. Ierendi and Minrothad have rangers that spend their lives circling the islands, looking for threats that have come ashore. Only Glantri does not approve of them, being divine spell casters they are banned upon pain of death.
Rogue The omnipresent rogue is found in every country in Mystara. Indeed, it would be hard to imagine a world without them. Any where you would find laws, you will find someone willing to skirt them. While rogues are more common to cities, even in the wilds of Ethengar and the pastures of the Five Shires you will find thieves and assassins. In some countries rogues are often encouraged like the Hin and Minrothad pirates, in places like Ylaruam or Rockholm the lives of the bad ones tend to be very short.
Once special type of rogue that has emerged is the rake. Rather than skulking around backstreets or searching for treasure in forgotten dungeons, rakes have taken on a much more dangerous environment, that of courtly politics. The arcane trickster archetype is present, but is found almost exclusively among the elves, or the wizardly nations of Alphatia and Glantri.
Sorcerer Sorcery in Mystara is very rare. There are no dragon hybrids, and magic is very stable. What Mystara does have is the Radiance. This mysterious power source exudes magic, and those that can tap into can become quite powerful indeed. Because the Radiance is located in Glantri, sorcerers come almost exclusively from that nation. Using the Radiance to power one's magic is extremely dangerous, and not to be taken lightly.
The other main source of sorcerers is the Shadow Elves. As they collect the Radiance touched soul crystals, they are exposed to the power more than even the wizards of Glantri. The number of Shadow Elf sorcerers tend to be higher than their wizards. Where Glantri sees the energy as a source to be exploited, Shadow Elves see it as a sacred duty to safeguard the Radiance.
Warlock Warlocks are extremely rare in Mystara, with magic so prevalent the need to barter for arcane power isn't a great one. Still there are always those willing to take short cuts. The major difference in Warlocks of Mystara and other realms is the source of their pacts.
There is one archfey that will deal with mortals regularly, than being King Oberon of the Dreamlands. He even receives mortals that can reach his court, there are portals all throughout the Known World but especially Alfheim. He is intrigued by the mortal races, and will often exchange mortals powers for a promise of future entertainment. The Fiend is represented by the creatures of the Nightmare Realm. Many creatures made of madness incarnate are willing to strike a bargain, though the cost is often too high to pay. For the Great Old One there is the Sphere of Entropy. Thanatos is more than willing to give power to further his goals, though a warlock openly serving this immortal will be not welcome in almost any setting.
Wizard In a magic rich world like Mystara, it is no surprise wizards are everywhere. Two nations, Glantri and Alphatia are ruled by them. Even lands that despise magic like Ylaruam you will find wizards, though tightly controlled. Every nation has at least one court wizard, and some the ruling classes are all magic users.
While most wizards study one aspect of magic or another, the Minrothad wizards tend to use their magic for financial gain. These merchant princes care little about how a spell is formed or focusing one type of spell over another, instead they want to know how to use their magic to increase profits. While using a charm spell at a trade meeting is forbidden, conjuring a water elemental to make your merchantman go just a little faster is standard practice.