Attributes: Strength, Speed
Skills: Medium Armor, Spear, Blunt Weapon, Athletics, Hand-to-Hand, Speechcraft
0. Deadman
1. Initiate
2. Bloodletter
3. Highwayman
4. Widowmaker
5. Harvestman
6. Winnower
7. Thresher
8. Reaper
9. Farmer
Guild Halls: no set halls, though commonly found around taverns and arenas. Perhaps have some sort of graffiti decal to mark their main hang-outs?
Area: members can be found in a very broad range from Narsis District to Telvannis, but mainly operate from large settlements in Mournhold District. Travelling members can be found on roads, otherwise they mostly stick to settlements with a lot of traffic passing through.
Description: A sort of duellist's guild who start, get involved in and escalate fights (but in a way that keeps to the letter of the law). Similarly to the Morag Tong, comes from a tradition of Daedra worship, in this case of Boethiah, though they now worship the warrior aspect of Almalexia. This faction has a predictably dubious reputation, and does not share the protections extended to the Morag Tong. To compensate, they have transitioned to Tribunal worship and, in their own way, respect Tribunal law. Players can become a member by defeating (not necessarily killing) other members; until then members will tend to be aggressive to the PC but not outright hostile. (If players ask a member to join the faction it will -- after a choice warning -- initiate a fight). Aside from general itinerant fight events, quests might involve fighting as someone's champion in a duel, seeking (generally non-lethal) fights with powerful or influential figures, clearing the guild or guild members of trouble when they invariably land in hot water, or punishing members when they break the rules.
While it doesn't go out of its way to keep the peace, usually the opposite, some quests can involve dungeon crawls to deal with bandits, cultists, dangerous critters etc. just because they're seen as worthy opponents. There could also be some group fights; either the player having to deal with multiple attackers, or the player teaming up with guild members to take someone/some people down. In some cases, the player could have the option of shaking down the opponent, though this would usually be frowned on. (Outlanders out east are usually fair game).
The concept here is that the Ordinators and Indoril generally have a pretty good handle on peacekeeping in Indoril lands, and content like Indoril bounty quests that might get expanded to the relevant areas, Fighters Guild quests and maybe even Legion quests will cover the rest. As such, rather than giving the player the role do-gooder, this faction would provide the player with an opportunity to explore the seedier corners of (especially) Indoril society, the darker aspects of Tribunal worship, and to add more interest to settlement zones rather than having all the action happen in the wilderness. I think we should have high-ish fight level thugs and muggers in eastern Morrowind settlements and roads either way (not all of whom would be members of the tong).

Attributes: Endurance, Willpower
Skills: Unarmored, Illusion, Alchemy, Alteration, Mysticism, Restoration
0. Applicant
1. Anointed
2. Novice
3. Mendicant
4. Healer
5. Physician
6. Pacifier
7. Miracle Worker
8. Minister
9. Archminister
Guild Halls: Hospices of St. Meris, which would generally be Velothi shrines (not full temples) or Velothi towers.
Area: operate mostly on the borders of House Indoril, though also to an extent in the interior of Mournhold district and parts of Telvannis.
Description: the opposite of the Harvester's Guild. A healer's guild. Provide aid to those who need it, in particular victims of house conflict, but also for instance patrols that encounter something nasty. Also provide general healing, and as such would encounter all layers of Dunmer society. Strictly pacifist. A lot of conflict deescalation, getting into awkward situations and getting the victims safely out, including the use of various spells. General concept here is a magical guild that doesn't focus on research and destructive aspects of magic like the Mages Guild and Telvanni, but on less direct pacifist solutions.
- intervene in a Morag Tong assassination or duel to keep the involved parties alive.
- go to the support of an Indoril patrol that was investigating recent activity at an old Daedric ruin.
- perhaps explore relations with the Mages Guild (would they accept the White Robe Guild's practices as religious observance or see it as unregulated use of magic outside of the guild? Obviously they wouldn't be able to threaten the Meris Guild, but might still be worth exploring).
- explore interactions with House nobles and others who might see the guild's activities as disruptive to House Wars, but would naturally be unable to be too outwardly disapproving. In particular, the obvious issues of having house nobles who are expected to perform their duties in the House War in the guild, who would probably need to protect their identities.

Attributes: Intelligence, Willpower
Skills: Blunt Weapon, Sneak, Unarmored, Speechcraft, Security, Mysticism
0. Ward
1. Student
2. Wanderer
3. Seeker
4. Scholar
5. Tutor
6. Master
7. Luminary
8. Secretkeeper
9. Secretmaster
Guild Halls: particular Velothi towers (generally not remote ones, some perhaps even in settlements Arvs-Drelen-style)
Area: in a broad line from southwestern to northeastern Morrowind, from Shipal-shin to Telvannis, (very roughly following the line of Veloth's Path), but more concentrated around Sacred Lands and Mephalan Vales
Description: Whereas most Dunmer scholars and theologians are tied to particular schools, often in Velothi towers, or factions like the Temple and Great Houses, the free scholars are a loose organisation that travel the land searching for and dispensing knowledge. The roots of the faction are ancient: during the Nord occupation of Morrowind, and perhaps in part inspired by the Nord clever men, reclusive Chimer scholars began travelling and communicating in secret, acting as a sort of information and reconnaissance network.
The ancient tradition has not survived into the modern day unbroken; over the centuries the free scholars have dwindled in number, died out and been revived repeatedly, generally being most active in times of adversity. The latest incarnation, which began emerging as Tiber Septim carved out an empire to the west, has been growing steadily in relevance under Imperial rule.
This faction's quests would revolve around seeking knowledge and secrets, such as finding skilled trainers, rare skill books, a lost relic or holy site. A lot of delving into lore and hard-to-find nooks and crannies of our gameworld, puzzles and riddles, but with plenty of practical benefits. In lower ranks the player would be taught useful skills, akin to the spells learnt doing chores in House Telvanni, whreas in later ranks the player will often take the role of teacher and become involved with various influential individuals. Shouldn't be as focused on ruin exploration as the IAS; they're not after history, but knowledge. Some specific examples:
- discuss theology with members of an esoteric society; attempt to uncover their hidden knowledge in the process. (Perhaps gaining a nice spell or something).
- investigate an abandoned Velothi tower that was home to wizard-scholars to recover their secrets.
- locate and train under a hostile high-level outlaw.
- negotiate with House Indoril to be present during a Daedric invocation to ask particular questions of the summoned spirit.

Attributes: Agility, Personality
Skills: Spear, Blunt Weapon, Light Armor, Athletics, Mercantile, Alteration
0. Bagman
1. Peddler
2. Courier
3. Outfitter
4. Trader
5. Caravaner
6. Navigator
7. Auctioneer
8. Magnate
9. Grand Magnate
Guild Hall: tradehouses and markets.
Area: operate along Morrowind's east coast including all of Telvannis.
Description: A guild of merchants and couriers that transports goods over dangerous and remote terrain; high risk, high reward. Interact with Dres Clansteads, Telvanni and other powerful beings. Specific quest examples:
- acquire (through trade or otherwise) and deliver a particular high-value item requested by a client.
- along with other guild members, escort some slaves over perilous (but with good pathing; think ashlands) terrain, ensuring they can't escape or get killed by threats.
- track down a guild member who met a bad end in the wild to recover and deliver the goods.
- extract payment from an uncooperative Telvanni client.
- negotiate a trade deal with the Zafirbel Bay Company, or some other kind of interaction (confrontational would work, too).