House Aetheryon: While House Targaryen was the most prominent family of Dragon Lords to escape the Doom and the most legendary, one set their eyes on Westeros long before. Nine hundred years before the destruction of Valyria, Aurys Aetheryon, the deposed Archon of Mantarys, departed his lost city with two thousand ships and two Dragons. For reasons known only to him, they bypassed the most prosperous parts of Westeros, sailing around the Iron Islands and laying siege to the North. House Aetheryon conquered the Western coast of the North. Crowning himself "The King of the Sea," he would spend the next forty years of his life warring with the Driftwood King until, at last, riding his mighty Dragon Morghul, he was sent crashing into the sea by a bolt of lightning.
His grandson. King Auryn bent the knee to House Stark, pledging the surviving Dragon to Winterfell. In exchange, they kept their domains which extend from Cape Kraken to the Gift near Shadow Tower. The Northern mountains are a source of precious gems and metals, and the Valyrian colonies along the Western coast are famous for their metal work. The world's most prominent silver veins are under house Aetheryon, and they share half their profits with House stark. Platinum mines and a rare type of blue diamond are one of the sources of the wealth of both the North and House Aetheryon.
The second is the Fyreleaf, a substance that was discovered on one of the legendary journeys of Aenar Aetheryon in 216 A.C. when dried; its leaves can produce distinctive aromas when smoked and are said to have dubious medicinal values, dried and compacted and rolled into larger leaves they can be smoked and create a stimulating sensation. They are a luxury good, and the "Drakes" or "drakos" as they're called, are smoked by most of the gentry and nobility in Westeros, with King Aegon's fifth laws creating enough prosperity for the Smallfolk to begin to enjoy them as well. And the third source of much of the North's wealth is the bittercane.
Strongcane/Bittercane/Strong Sugar: it goes by many names, but it is the source of House Aetheryon's enormous wealth (and much of house Stark's as well.). When inhaled or mixed with a tonic, it can be a remarkable painkiller and an alternative to the more addictive milk of the poppy. It is also an excellent treatment for melancholia and lethargy, and the greatest single client is the Citadel which consumes a quarter of all Strongcane brought into the realm. Maesters across the realm use it to treat various ailments and speculate that it is a potent sugar cane that adapted itself to cold climes (Though no one truly knows where they get this, it is only ever seen in its refined form.). Used recreationally, both in Essos and Westeros, it can produce a sense of euphoria and rapidity of mind; however, most Maesters strongly caution against it.
The deleterious effects when abused are pretty extreme; it is believed part of the madness of King Aerys lies at the feet of his recreational use of bittercane to quell nightmares after the defiance of Duskendale. The Lord of the Rock Tywin Lannister executes any merchant selling bittercane to anyone, not a member of the gentry or the nobility or who doesn't Wear a Maester's chain, and passed laws within his domain regulating its consumption. House Aetheryon protects its method of cultivation and refinement, and the seeds of this plant as violently as house Blackfyre protects the secret to Valyrian steel, and House Tyrell protects their silkworm farms.
The Aetheryon trade fleet is said to be surpassed only by the Redwynes in size, and through it, the Iron Born were traditionally forced to contain their invasions of the Southern Kingdoms.
House Aetheryon is fanatically loyal to House Stark and has remained so since bending the Knee. The reasons for King Auryns' submission when he still had one of his grandfather's dragons remain unknown.
During the reign of Jaehaerys I, the conciliator House Aetheryon was reduced to only nine bastards and four trueborn sons. Seeking to maintain a Valyrian house and perhaps sensing that the Valyrian colonies in the North would be ungovernable if not for an Aetheryon or perhaps seeking more significant trade ties with House Stark. Saera Targaryen was wed to Vaelos Aetheryon, and his brother took Viserra to his wife. The Union of the blood of dragon lords was the first in recorded history.
After the union of the two surviving Dragon Lord bloodlines, house Aetheryon began adopting Targaryen names.
The Current lord of house Aetheryon is Aemon Aetheryon, the great-great-grandson of Aenar Aetheryon. They are known for their bone-white and silvery hair and turquoise eyes.
Houses Mormont, Ryswell, Forrester, and Glover are sworn to them.
Sigil: An ermine Sea dragon on an indigo field with seven silver stars overhead.
Their house words: "From the depths, we rise."
House Tully of Harrenhal: Founded by Ser Hoster Rivers, a Tully-born great bastard of Aegon the unworthy, and his sister-wife Minisia Rivers. He was given the right to take the name Tully by his uncle, the lord of Riverrun. They are a powerhouse of the Riverlands and the only family to defeat the Harrenhal curse. House Tully of Harrenhal is connected by blood and marriage to Houses Blackfyre and Targaryen and has one of the most potent blood claims to the Iron Throne next to the Blackfyre's and produces some of the finest Knights in the realm.
Their sigil is a silver three-headed dragon in flight on a field of blue and red.
House words: As true as steel.
Current House head: Gaemon Tully who in his youth was said to be the greatest sword in the realm.
Heir apparent: Brynden Tully, the younger, named after the legendary Blackfish. Grandson of Lord Gaemon
House Tully of Riverrun: Due to the Conqueror taking a keener interest in the affairs of the Kingdom, he created by edict. The Riverlands are often referred to as an extension of the Crownlands that happen to have a Paramountcy. Wealth from trade and canals have made House Tully and its vassals powerful. Their river fleet kept the King's peace for centuries before it was decimated by the royal fleet during an abortive attempt to besiege the capitol by the river. House Tully is a proud house of Andal customs and First Men blood, yet over the last century and a half, they've married enough Targaryen spares into their house that it's often said a riverwyrm should replace the Tully trout.
House Words: Family, Duty, honor.
House Blackfyre of the Narrow Sea: After unveiling the conspiracy to force him onto the Iron Throne, Daemon Blackfyre and his six sons were given Dragonstone as their seat, and the Paramountcy of the narrow sea was created. Daemon Blackfyre expanded his domain with leave from his brother, conquering the stepstones and then Tyrosh itself after a slave rebellion resulted in overthrowing its government.
Through trade and the commerce of Tyrosh. House, Blackfyre is often said to possess wealth that rivals even the Lannisters and the Starks.
House Blackfyre was allowed to keep the sword Blackfyre, with house Targaryen keeping dark sister as its official sword.
Before the Conjuring at Summerhall. House Blackfyre discovered the secret to producing Valyrian steel. Valyrian steel weapons are rare, owing to the obscene cost of their creations. A Valyrian steel dagger might cost thirty thousand Gold Dragons. Their legendary sword sets done in the Lengii style (Containing a great sword or a bastard sword, a broad sword, two dirks, and two daggers. Customed to the paying House's colors and inscribed with the House words.) are known to cost between one hundred thousand and a half a million gold dragons. Their suits of Valyrian steel armor are the most expensive of their works. Costing a million gold dragons at a minimum.
The Citadel also orders a plethora of Valyrian steel chain links from their forges as there has been an increase in novices taking up the Higher Mysteries. To date, only Tywin Lannister knows how they make their Valyrian steel, and he has kept the secret to himself. Whether out of affection for the house of his Goodson or because he views it as leverage is the subject of much debate.
House words: No better friend, No fiercer foe.
Current house head: Prince Aegon Blackfyre (for the narrow sea/Essos branch.) and King Daemon Blackfyre the first. Jacaerys Blackfyre is the heir apparent to Aegon. And Prince Daeron is the presumptive heir to the Throne.
House Sunfyre of Lannisport: The Westerlands also welcomed Valyrian smiths and colonists seeking a life away from the intrigue and murders of the Freehold. The Kings of the Rock never ennobled any Valyrians. Instead, they became wealthy members of the gentry. Their gold smithing, engineering, and the construction of Valyrian roads in the west meant they were rewarded ably. It wouldn't be until the Great Spring sickness decimated Lannisport and wiped-out house Lannister of Lannisport, leaving only a handful of daughters, that their prospects changed.
Gaemon Hill, a bastard son of Daeron the second (And some Maesters believe the youth was a Blackfyre bastard.), a famed Knight and Captain of the Lannisport watch whose actions to quarantine the city prevented the disease from ravaging the rest of the west was ennobled. Gaemon Hill owned several gold mines and was often called 'Sunfyre reborn' by the Lord of the Rock, and so in his honor, he took the name Sunfyre and married Joanna Lannister of Lannisport. Rising as the mayor Lord of Lannisport, house Sunfyre is fanatically loyal to the Lions of the Rock. With Ser Aethan Sunfyre serving as the sworn sword of Tywin Lannister. Loyal to House Lannister. They are known for their golden hair with silver streaks and amethyst eyes.
Current lord: Tytos Sunfyre, heir apparent Aegor Sunfyre.
House Words: 'Neath the glittering gold, the Dragon's fire.
Sigil: A gold sea dragon on a red and blue field quartered by sea lions