So with the advent of D&D 5e, I've been pondering how it all applies to Terrima. (I really like the new edition, btw.)
The playable races are: Humans, half-elves, and dwarves. Half-elves are re-fluffed as humans with a smidge of elvish blood generations back. (They therefore interbreed with humans and each other to generally produce "half-elf" kids.)
The classes in order:
Barbarian: Berserkers will be found in Thule, of course. Totem warriors among the Rovers and the steppe tribes.
Bard: The Lore bard is a perfect fit for the elven Loresingers. Not bad for riddle-men as well, if there are any still around. There just aren't many bards in Terrima, though, and I'm not seeing a natural slot for Valor bards at all. Still, adventurers are exceptional people, right?
Cleric: For now, priests of the Light work just fine with domains of Life (Service), Knowledge (Inquiry), Light (Union), and War (Guard). However, I am ultimately going to have to rework them - Union in particular is going to need changes.
Ideally, I'd like to see priests get a limited set of 'spells known' like sorcerers, but that'll have to wait on the DMG.
Druid: They're around, mostly keeping a low profile. (They can be a little more open in heavily Kelhic areas like Melendor and among the Rovers.) Very loosely organized. Most are probably Circle of the Land, but there's no reason why there couldn't be Moon Druids. They aren't separate groups, though, just druids with different emphases.
Fighter: The mundane subclasses are fine, of course. The Eldritch Knight is *perfect* for war-wizards. And in Novalis, the 'Knight' in that is meant whole-heartedly. Magic-using knighthoods are a Thing.
Monk: The Tear-monks are Way of the Open Hand for now. In time I'll probably create something unique for them - Quivering Palm is just not right for them, in particular. I might have to wait until I see what they do with psionics, as in Terrima, ki is pretty much psionic in nature.
Way of the Shadow is perfect for Cacothist cultists and so on. Way of the Four Elements does not really have a niche, at any rate in Occida.
Paladin: In the end I may just say that the Order of Guard are paladins with the Oath of Devotion and call it good. Oath of the Ancients... Feels elvish to me. I could see it happening in Melendor, but it's probably quite rare. I have mixed feelings about the Oath of Vengeance - it doesn't feel like something the Light would go in for, but it could maybe happen in the Empire or the Shards?
Ranger: The spells are a little annoying to fit in. Hunters largely fit the world's theme (and my gut) better than Beastmasters.
Rogue: I really love the Arcane Trickster, but darned if I see how it fits into the world. There is just no niche for it in the history, whether IC or OOC. If they were more sorcery-based and working off Charisma, then MAYBE. The Thief and Assassin are fine, of course.
Sorcerer: The Draconic Bloodline is right out: Terriman sorcerers are Wild Mages. (The Wild Surge table with have to be drastically reworked, though - less Wand of Wonder, more Rare Marvel.) Though if they ever come up with a Genie Bloodline, that might work for the Sirinese sorcerers.
You'd think a Fey Bloodline would be perfect for Occidan sorcerers, but my gut is skeptical.
Warlock: These guys are very interesting, but do not really fit into the world. With one exception: The Fey Pact is just about right for the Islander Shamans, with the understanding that their 'patron' is really the spirits of the islands as a whole. Pact of the Blade is not really right for them. Most of them are Pact of the Tome, I think, with their 'tomes' being the ancient writings on the Standing Stones that they go on to tattoo on their bodies. Pact of the Chain can work, but the imp, quasit, pseudodragon, and sprite are all wrong for them. I might just let them give sprite powers to one of the 'standard' familiars.
The Shamans also will have their own Background, which will have some very entertaining personality quirks, Bonds, and so on.
Fiend pact can certainly exist, but let's face it, everyone is gonna want those guys' blood - the only way they are going to last is by hooking up with Cacothists. Great Old One is right out.
Wizard: I'm not 100% happy with the explicit ties to the schools of magic, which I dislike. But these are certainly the most functional specialist wizards ever (not counting the AD&D Illusionist!). Evocation and Abjuration were the first forms of wizardry to be created, so they are quite common Traditions. Enchanters still have an insidious air around them, because they were responsible in part for the fall of the Empire. Transmuters might not exist, as they have an alchemical flair to them that doesn't quite feel right to me.
Ultimately I'm going to create my own Traditions. Things like, "Aurelian War-Wizard", "Loresong Graduate", etc.
I'm really going to have to see what they come up with for psionics before I can make any decisions about the Protectorate.
But the Antimagoi are probably going to be a heavily tweaked sorcerer. Well, in theory - in practice they're going to be a heavily tweaked Eldritch Knight. (And perhaps Arcane Trickster - they're the spy branch.) In essence, they can only spend their slots on things like counterspelling, dispelling, and ruining mages' lives in general.

Oh, and on detecting magic, of course.