All classes present in the 5e SRD are available in Farland. What follows is a discussion of the role of each class in the liberated and occupied kingdoms. Some of those classes will be socially stigmatized, but that depends where the PC is in the continent of Farland. In the liberated Kingdoms (Kale, Kelerak, and Daven) things look much brighter-- fighting classes are common and even revered, and clerics and paladins are not rare anymore. They get great respect. Spell casters might still be looked on with suspicion, but the great deeds they have done after the liberation has gained them a new place in the heart of the citizenry.
In the occupied kingdoms (Zeland, Orland, and Farland), oone could certainly play any of the non-fighter classes-- as long as they serve evil or make a pretense to do so, pay somebody off or have connections, hide it, or find some other creative way to get around the restrictions. Rogues are common everywhere. The options are, in fact, fairly numerous.
Bards-- As performers and minstrels, bards are welcomed in the liberated kingdoms, and they serve many roles, acting as doctors, entertainers, soldiers, and diplomats.
New bard colleges are detailed here.
Clerics-- For the first time in nearly 400 years, the priests of good and neutral gods have nothing to fear in the liberated kingdoms. They continued to exist secretly during the Dark Times, and when the liberation came they were called upon by the masses to provide spiritual, magical, and military support. The churches have flourished and have regained a substantial part of their power, although not all of it. Being a priest of Grlarshh or The Dark Walker is punishable by death in the Liberated Kingdoms. To receive spells in Farland, priests must pray to one of the true gods. A priest on the world of Núrion (where Farland is located) who worships any other deity or lesser deity cannot receive prayers (spells).
Druids-- As nature priests, druids in the liberated kingdoms are honored and are often called upon for help with farming, controlling animal infestations, and providing herbal medicines.
Fighters-- Fighters are plentiful in the liberated kingdoms. As always, fighters may be found serving as men-at-arms, assassins, adventurers, hired swords, etc. Different races and geographical areas are known for producing fighters who specialize in different aspects of warfare; for example, Kelerak produces master Longbowman.
New fighter archetypes are detailed here.
Monks-- Monks in the liberated kingdoms are extremely rare. Any who are found there probably migrated from Yrrkune or one of the occupied lands. Monks are looked upon with curiosity and even awe by citizens of the liberated kingdoms.
Paladins-- In the liberated kingdoms, paladins are revered and are in high demand.
New paladin oaths are detailed here.
Rangers-- Rangers sometimes congregate in loose groups so they can better patrol and protect an area. These groups are generally quite popular in the liberated kingdoms and serve the rulers in a loose way. The most famous group of rangers was the Elven Shadow Walkers. Bestraville in Kelerak also has a famous group of ranger-protectors called the Woodsmen.
New ranger archetypes are detailed here.
Rogues-- Thieves have come under some pressure in the liberated kingdoms as the new rulers seek to dislodge the entrenched and powerful guilds that flourished under the rule of evil. Still, there is no shortage of the criminal elements in the still-anarchic liberated cities. Rogues who are not thieves are also plentiful in the liberated kingdoms, serving as diplomats, operatives, and skilled soldiers.
Sorcerers, Warlocks, and Wizards-- Magic and those who use it tend to be looked on with suspicion by the masses. Even still, magic has recently gained a great deal of acceptance in the liberated Kingdoms, as a result of the work that some magic users have done to keep the kingdoms free, and also as a result of the legitimacy granted to these magic-using classes by the rulers of the free kingdoms who have sanctioned their activities and even hired them. A Battlemage College (designed to produce War Wizards to support the Kelerite armies) has recently been started in Dragonspur City.
New warlock pacts are detailed here.
Bards-- Bards are not unwelcome in the occupied kingdoms, as long as they tow the party line and work to forward the propaganda of their Lord of Sin.
New bard colleges are detailed here.
Clerics-- Being a priest of anything but Bel or Vornoth, the Dark Walker is forbidden in occupied lands under penalty of death, but the faithful do it anyway. They have learned to operate clandestinely, not indicating outwardly that they are priests and holding their religious ceremonies in secret and isolated places. They support the oppressed populace, providing them with spiritual guidance, and in return are supported by the masses. They must always beware of spies, however. Priests of Bel and Vornoth, especially the latter God, flourish in the Occupied Lands and are in high demand by the evil rulers, if not by the human population (even though the people are forced to attend Black Mass at the Church of Vornoth the Dark Walker). To receive prayers (spells) in Farland, priests must pray to one of the true Gods. A priest on the world of Núrion (where Farland is located) that worships any other God cannot receive prayers.
Druids-- Druids in the occupied lands must either swear allegiance to Vornoth-- a proposition which most of them find extremely distasteful-- or seclude themselves in distant woodland groves.
Fighters-- Warriors are as common in the Occupied Kingdoms as they are in the Liberated Kingdoms. The Dark Races value military might and produce powerful fighters. Hobgoblins, particularly, produce great warriors. Human warriors, of course, are also plentiful. All are in demand.
New fighter archetypes are detailed here.
Monks-- Kunese monks in the occupied kingdoms are generally there by leave of the dark powers, or assumed to be, so they are usually left unmolested. A powerful order of goblin monks from Farland called The Way of the Claw has brought knowledge of monkish ways to the average citizen of the occupied kingdoms.
Paladins-- Generally worshipping the good gods, paladins are rare in the occupied kingdoms and face great danger there. The evil rulers always attempt to eliminate paladins. Many paladins do still exist secretly in these kingdoms, however.
New paladin oaths are detailed here.
Rangers-- Good rangers certainly exist in the Occupied Kingdoms and serve much the same function; they just face more difficulties. Their skill in woodlore, however, makes hide-and-strike tactics highly effective and limits their immediate danger. The evil rulers also employ rangers and ranger-groups. The most famous of these are the Hounds, a slave-hunting force employed by the Lord of Envy in Orland.
New ranger archetypes are detailed here.
Rogues-- Thieves and rakes tend to prosper in the Dark Kingdoms and form powerful guilds. These guilds are often in league with the evil rulers and pay them large tithes. Rogues are also common, serving as operatives and skilled fighters or assassins.
Sorcerers, Warlocks, and Wizards-- Magic and those who use it tend to be looked on with suspicion by the masses. Some mages have been burned at the stake as witches. It is not wise to flaunt a wizardly class in the occupied kingdoms. In fact, it is generally illegal under the rule of evil, but is often overlooked for a small fee. Of course the dark races employ magic users who are sanctioned by the evil rulers, and these are in fact fairly common. They wear a special badge or mark that indicates to the populace that these wizards are official and are not to be molested.
New warlock pacts are detailed here.