New minor factions. Canon/Made-up. And explain why they were placed where they were placed.

Holy Wardens - "Holy Wardens of La Maisontaal", which is actually a WHTW invented thing, a regiment of renown. But they represent Maisontaal who have beef with Arkhan and otherwise don't have a military order to fulfill this role. Oh and the faction leader is a canon character, I think she's associated with Maisontaal somehow.
Knight-Avengers of Brionne - Berenger Vaillancourt is a canon character. It's a bit random him being in the Mountains of Mourn, other than the "Quest's End" region being associated with bretonnia. The nearby Tzeentch faction has a cultist called "Rainouart Ducharme" which ties it all together nicely.
Leofric's Fellowship - Leofric Carrard is a canon character. A bretonnian knight sitting in an Arabyan city, makes sense to me.

Apehorns Tribe - Made up. Referencing the Apemen of the southlands (this faction placed in Araby, close enough)

Black Kraken Armada - This is supposed to be Tordrek Hackhart's faction. But I left him out as the faction leader, exercise for the reader (modder).
Laborfleet of Uzkulak - Sort of made up. Abnagg Hellbeard is a canon Chaos Dwarf admiral so, it's not too far off.
House of Khorakk - Khorakk from the Wulfrik novel

For these, locations, colors, symbols are all made up. But the faction leaders and/or name of the faction comes from White Dwarf content:
Fists of Hashut - White Dwarf 203
Horns of Hashut - White Dwarf 170
House of Azeros - White Dwarf 325
House of Baal - White Dwarf 203
House of Bzaark - Anurell's Tomb one, can't remember
Snakebeard's Artificers - White Dwarf 103
Slaves of the Black Dwarf - White Dwarf 201

Horde of Kurnz - WH3 Prologue
Slayers of Souls - Canon
Soulbane Witch-Cabal - Canon
Steelfist Reavers - Canon
The Scourgeborn - Canon, faction leader is some lieutenant of Anfingrimm

Crimson Corsairs - Canon
Darkness Daughters - Canon, Leanora Navrre is a named Necrofex Colossus, so building a faction around that concept.
Rawhead Reavers - Jacque Rawhead gets a passing mention in the Dreadfleet novel. Not actually vampire coast, just a pirate. But I think it also says he's dead, so maybe it works out.
Red Hand Fleet - Canon, from a Gotrek&Felix story I think
Schmidt's Renegades - Canon, from Man O War. Not actually vampire coast, just pirates. But anything can happen at sea.
Spirits of Norvard - The Sea Hag is a real character. Norvard is the Ungol name for Erengard. It's not great, but vampire coast is the best culture that represents this.

Agents of the Moon - Canon. Placement in east Nehekhara... well there's a whole thing with Lahmia and Cathay in the distant past. Not the strongest, but it's something.
Sea Dragon's Castaways - Canon-ish. Placement in Galleon's Graveyard is appropriate.
Dark Land Bandits - Canon-ish. "Bandits of the Silver Road" is a Cathay ror.
Labourers of Zharr - Made-Up, slave revolt faction

Corsairs of Spite - Canon.
Harbingers of Pain - Canon.
The Dark Convent - Canon.

Bugman's Brewery - Canon.
Clan Barruk - Canon. Minor dwarf clan. Placement is... alright. Looking for oathgold in the swamps?
Clan Durazgrund - Canon. Placed close to Karak Ungor, which they wanna take back.
Karak Izor - Canon, vanilla flag.
Kraka Ravnsvake - Canon.
Chained of Zharr - Made-up, slave revolt faction

Altdorf - Canon, faction leader is canon too. Having this preserves the 1-region start for Karl. (There's a mission to confederate on turn 2-3 if you didn't know).
Archaeological Expedition - Canon, can't remember if the faction leader makes sense, but he's a real dude
Carroburg - Canon, WH1 flag. Why are they independent? It's interesting, breaks up Middenland which would be enormous otherwise, Solland is already in, might as well add Drakwald. It just snowballs out of control.
Cult of Morr - Canon. I think specifically they should be "Knights of the Raven", like that's what the faction leader implies.
Cult of Ulric - Canon, WH1 flag. Specifically they should be "Order of the Winter Throne", both their location at Ulric's throat and the faction leader support that.
Sigmarsheim - Canon
Solland - Canon, sort of. WH2/WH3 has it as an elector count position. it's hard to remove things lol.
Fallow Hills - Canon. Starts dead. Having an Empire-culture version of Mootland keeps things tidy. Really they should only be releasable from the Gipfel region.
Sylvania - Canon. Starts dead. name is a bit awkward in retrospect (exact same as the vmp faction)
Westerland - Canon. Starts dead. It's just what Marienburg/Wasteland used to be called. Allows for both the vanilla Marienburg faction to remain outside the empire, and for something nice to be releaseable there.
Grauesland - Canon. Starts dead. Boundaries guessed.
Lichtenberg - Canon. Starts dead. Boundaries guessed.
West Mark - Canon. Starts dead. Boundaries guessed.

All these are canon and reasonably placed:
Bad Axes
Black Spider
Bloodfeather
Blue Face
Bog Creepers
Burning Face
Cluster Eye
Crooked Eye
Da Howlaz
Deff Grindaz
Gloomfang
Grag-A-Mugar Clan - Hobgoblins, Something Rotten in Kislev
Grey Hag
Ironback
Ironclaw Mutinous Boyz
Ironskinz
Nag Rippers - Hobgoblins
Necksnappers
Reavaz
Red Shield
Rusty Daggaz
Spotted Skullz
Stitched Skullz
Stone Fangz
Vulchaz
White Skullz
Withered Eye
Yellow Eye

Continental Exarchate - Canon.
The Starguided - Faction leader is canon. Placement in Galleon's Graveyard is... reasonable.

Third Host of Murder - Canon
Blood-Sayters - Prologue
Akhar's Hunters - Made-up
Insensate Rage - Made-up
Unfettered Fury - Made-up

Dervingard Garrison - Prologue
Heldegrad - Well it's a city, on an Alfred Nuñez Jr. map (which is canon enough for me). And it ends with -grad. And I was planning on putting some weirder factions in the Border Princes anyway (like a Cathay faction that never panned out). Soooo....
Order of the Winter Sun - Canon. Being in the Badlands is completely random, and for variety. Although Zandri road isn't too bad, like that's a place guarded by mercenaries. (Also it's an amusing inverse of Order of the Blazing Sun's placement)
Peasant Council - Made up
Rota of the Dawn - Canon
Boyar Assembly - Made up
Tzaryovshchina - Made up. This is supposed be like "Movement in favor of the Tzar". I've been told that it's a reasonable rendition of that. They're supposed to be pro-Katarin, anti-Kostaltyn, and are lead by a certain guy from WH1/WH2 Kislev. (Kislev.)
Wheatland Colonies - Canon
Chattel of Zharr - Made up, slave revolt faction

Gorehunt Tribe - Canon. Being "native" to Araby is of course nonsense, they just raided and died there. But it gives Sigvald another direction to expand.
Brennuns - Passing mention in... something. I remember it's listed alongside the main Norscan tribes like Skaeling, Graeling, etc. So I put it in the Norsca empty spot.
Gharhar - Canon. (the vanilla faction is WoC)
Hastlings - Canon
Losteriklings - Losterik is a real character, having a group of people emulating him and faffing about in Albion is made up.
River Dolgan - Canon. Something Rotten in Kislev. The "River" distinction is in there.
Schwarzvolf - Canon. I explain this in the other thread, but I don't think they live on the Norscan peninsula. And yet they're still close enough where you could say they were Norscan (and not Kurgan or Tong).
Servants of Mermedus - Canon-ish. The faction leader is canon, mentioned in the Sea of Claws WFRP book. Placement in Galleon's Graveyard is made up.
Svengarlings - Svengar is a real character. Again, people emulating him, or naming themselves after him, thousands of years later is made up.
Tahmaks - Canon
Tokmars - Canon
Ursfjordlings - Canon

Festant Flux - Faction leader is canon
Pox Matriarchy - Faction leader is canon
Tide of Defilement - Faction leader is canon
Gibbeting Decay - Made-up
Phlegmatic Humor - Made-up
Putrid Musk - Made-up

Angry Fists - Canon
Backbreakers - Canon. Placement is an amusement, because Devil's Backbone.
Black Maw - Canon
Bulgers - Canon
Deathtoll - Canon
Ironskins - Canon
Payswords - Canon
Red Maw - Canon
Rockeaters - Canon. Placement is reasonable, close to the Empire where all their canon takes place.
Suneaters - Canon. Placement is an amusement, because Circle of the Sun.
Thunderhoof - Canon. Placement is reasonable, although it's a bit wacky with the Crimson Legion also being a faction, and no where close by...
Thralls of Zharr - Made-up, slave revolt faction

These are all canon:
Clan Crooktail
Clan Festerlingus
Clan Flem
Clan Gowjyer - Passing reference in... something. I just like the name. Placement in the Bury Bone Hills is completely random and done for variety.
Clan Gritak - Should be extinct already, but that is sure to happen within a few turns
Clan Grutnik
Clan Klaw
Clan Rikek
Clan Rikket
Clan Scruten
Clan Skaar
Clan Skab
Clan Skaul
Clan Skrapp
Clan Skully
Clan Skuttle
Fester Clan-Nest - Warhammer: Vermintide II Chaos Wastes.

Addled Minds - Faction leader is canon
Worshippers of the Worm - Non-Canon. This is based on some unpublished Araby adventure thing "Relics of the Crusades". It's... semi-canon. Maybe. Anyway, the Caverns of the Worm (made-up) was under the Plains of Haytin (canon, that one Araby map). And there were unspecified cultists. *If* they're Slaanesh cultists, then it becomes a funny sex joke. So here we are.
Coveted Passion - Made-up
Loesh's Indulgence - Made-up
Obsessive Perfection - Made-up
Serpent's Harem - Made-up

Esteban's Caballeros - Canon-ish. "Esteban of Estalia" fought in the great crusade near Shanidaar. One can imagine a knightly order based on him. Faction flag design and colors come from some OldHammer estalia thing.
Pigbarter - Canon. But the use of the TEB culture annoys me. Ogres would be lame, as they're are clearly men living there. Really I think an "Ind" cultured faction would be the best choice, but that's not an option.
North Confederacy - Made-up. I meant to replace these.
Central Confederacy - Made-up.
South Confederacy - Made-up.
Luccini - Canon
Miragliano - Canon
Pavona - Canon
Tobaro - Canon
Trantio - Canon
Verezzo - Canon
Remas - Canon
Bilbali - Canon
Magritta - Canon
Monte Castello - Canon
Reinos Pobres - Canon-ish. They poor, they kingdoms.
Vizeaya - Alfred Nuñez Jr. map...
Nuja - Alfred Nuñez Jr. map...
Almagora - Alfred Nuñez Jr. map...
Gualcazar - Alfred Nuñez Jr. map...
Order of the Blazing Sun - Canon. Placement on Svunumm, canon.

Mahrak - Canon
Quatar - Canon
Zandri - Canon. Faction leader is the Zandri king who fights Luthor in End Times.
Guardians of the Valley - Faction leader is canon.
Settra's Revenge - Canon
Sutekh Dynasty - Canon-ish. The character is "Prince Sutekh". Placement in Bel Aliad is canon.

There's a map called "The Extent of King Alcadizaar the Conqueror's Realm" there are three labels, one for each of these factions:
Vulture Fleet - Canon. Placed in Tilea.
Crimson Legion - Canon. Placed in the Dark Lands. Would also make sense in the Mountains of Mourn. Didn't do that, I got a theme to stick with.
Legion of Setep - Canon. Placed in/around/through Black Fire Pass.

Swords of Change - Faction leader is canon.
Cult of Mirrors - Non-Canon. Don't get me started. Read the other thread.
Golden Stewards - Canon-ish. Galleon's Graveyard in TOW is set after Noctilus loses in Dreadfleet and the Golden Magus takes over. So I see the Golden Magus leaving his stewards in charge (Oh spoilers for Dreadfleet, Golden Magus is a Tzeentch worshipper).
Aquiline Trickery - Made-up.
Scheming Horrors - Made-up.
Soirée of Sorcery - Made-up. Partypus reference lol
The Pearlescent - Made-up.

Boradin Coven - Canon. Ulrika novel thing. Should really be in Praag.
Cult of Mordig - Canon
Ghost of Glanborielle - Canon
Keepers of the Mountain - Canon. Nagash novel thing.
Rametep Dynasty - Canon
Sigmar's Brave - Canon. Tome of Corruption. They all died, hence the Hill of Bones region. Yes, vampire counts because I say they were resurrected by a necromancer.
The Everliving - Canon
Wamphyro Cabal - Canon

Piña Colony - Made-up. Alfred Nuñez Jr. map thing.
Dune Sa'aali - Other thread explains it
Spirits of Sherweald - Don't get me started, look at the other thread.
Spirits of Sussurrio - Made-up. Alfred Nuñez Jr. map thing.

WH1 factions:
Anmyr
Arranoc
Atylwyth
Cavaroc
Cythral
Fyr Darric
Modryn
Tirsyth