Most Distinguishable Physical Feature of Each Great House

As it is one of the larger plot points in A Game of Thrones, I thought it would be fun to list out the Great Houses (and a few others) and show repeating/common physical features.

The seed is strong, Jon Arryn had cried on his deathbed, and so it was. -AGOT, Eddard XII

Background

This is a fantasy series and not based on real DNA/Punnett squares.

Targaryen

The Targaryens are the blood of old Valyria:

The great beauty of the Valyrians—with their hair of palest silver or gold and eyes in shades of purple not found amongst any other peoples of the world—is well-known, and often held up as proof that the Valyrians are not entirely of the same blood as other men. Yet there are maesters who point out that, by careful breeding of animals, one can achieve a desirable result, and that populations in isolation can often show quite remarkable variations from what might be regarded as common. This may be a likelier answer to the mystery of the Valyrian origins although it does not explain the affinity with dragons that those with the blood of Valyria clearly had. -TWOIAF, The Rise of Valyria

If interested: The Blood of Old Valyria Part I: List of Current Characters with Valyrian Blood

Baratheon

House Baratheon is known for their black hair and blue eyes:

All those bastards, all with hair as black as night. Grand Maester Malleon recorded the last mating between stag and lion, some ninety years ago, when Tya Lannister wed Gowen Baratheon, third son of the reigning lord. Their only issue, an unnamed boy described in Malleon's tome as a large and lusty lad born with a full head of black hair, died in infancy. Thirty years before that a male Lannister had taken a Baratheon maid to wife. She had given him three daughters and a son, each black-haired. No matter how far back Ned searched in the brittle yellowed pages, always he found the gold yielding before the coal. -AGOT, Eddard XII

If you are interested: Who is the 8th bastard of Robert I Baratheon that Varys knows of? & Unlikely Potential Bastard of Robert Baratheon

Stark

And her betrothed looked at her with the cool grey eyes of a Stark and promised to spare the boy who loved her. -AGOT, Catelyn VII

and:

The boy absorbed that all in silence. He had the Stark face if not the name: long, solemn, guarded, a face that gave nothing away. Whoever his mother had been, she had left little of herself in her son. -AGOT, Tyrion II

and:

Arya had her father's eyes, the grey eyes of the Starks. A girl her age might let her hair grow long, add inches to her height, see her chest fill out, but she could not change the color of her eyes.

Like the Targaryens and dragonbonding, the Starks have seemingly shown the potential for warging. If interested: The Origins of the Stark Warging Powers

Lannister

The Lannisters are known for their green eyes, blonde hair and tend to be attractive:

This Ser Cleos Frey was a son of the Lady Genna who was sister to Lord Tywin Lannister, but he had none of the fabled Lannister beauty, the fair hair and green eyes. -ACOK, Catelyn I

and:

The king was clad in a gilded breastplate with a roaring lion engraved upon its chest, as if he expected the war to engulf them at any moment. He was thirteen today, and tall for his age, with the green eyes and golden hair of the Lannisters. -ACOK, Sansa I

and:

It seemed to Tyrion that the lad had grown three inches since being knighted. Lancel had thick sandy hair, green Lannister eyes, and a line of soft blond fuzz on his upper lip. -ACOK, Tyrion VI

Arryn

While Sweetrobin has brown hair, it seems like the Arryns may potentially have a look:

Ser Harrold Hardyng looked every inch a lord-in-waiting; clean-limbed and handsome, straight as a lance, hard with muscle. Men old enough to have known Jon Arryn in his youth said Ser Harrold had his look, she knew. He had a mop of sandy blond hair, pale blue eyes, an aquiline nose -TWOW, Alayne I

Martell

In the words of the Young Dragon, the Martells would be considered salty dornishmen:

The Young Dragon, King Daeron I Targaryen, gave them the names we know them by in his book, The Conquest of Dorne. ... the salty Dornishmen of the coasts, dark-haired and lithe and oliveskinned, have the queerest customs and the most Rhoynish blood. (When Princess Nymeria came ashore in Dorne, most of her Rhoynar preferred to remain close to the sea that had been their home for so long, even after Nymeria burned their ships.) -TWOIAF, Dorne

Tully

The Tullys tend to have high cheekbones, thick auburn hair and blue eyes:

It wasn't fair. Sansa had everything. Sansa was two years older; maybe by the time Arya had been born, there had been nothing left. Often it felt that way. Sansa could sew and dance and sing. She wrote poetry. She knew how to dress. She played the high harp and the bells. Worse, she was beautiful. Sansa had gotten their mother's fine high cheekbones and the thick auburn hair of the Tullys. Arya took after their lord father. Her hair was a lusterless brown, and her face was long and solemn -AGOT, Arya I

and:

Sansa could never understand how two sisters, born only two years apart, could be so different. It would have been easier if Arya had been a bastard, like their half brother Jon. She even looked like Jon, with the long face and brown hair of the Starks, and nothing of their lady mother in her face or her coloring. And Jon's mother had been common, or so people whispered. -AGOT, Sansa I

and:

Catelyn had always thought Robb looked like her; like Bran and Rickon and Sansa, he had the Tully coloring, the auburn hair, the blue eyes. -AGOT, Catelyn III

Tyrell

The Tyrells tend to have curly brown hair and brown eyes:

the girl no older than Robb, very pretty, with a doe's soft eyes and a mane of curling brown hair that fell about her shoulders in lazy ringlets. Her smile was shy and sweet. -ACOK, Catelyn II

and:

the Tyrell girl splendid in green with a cloak of autumn flowers blowing from her shoulders. She was sixteen, brown-haired and brown-eyed, slender and beautiful. -ASOS, Sansa I

and:

Lord Mace Tyrell, a heavy, robust man with curling brown hair and a spade-shaped beard well salted with white; -ASOS, Tyrion III

and:

Slim as a sword, lithe and fit, Ser Loras Tyrell wore a snowy linen tunic and white wool breeches, with a gold belt around his waist and a gold rose clasping his fine silk cloak. His hair was a soft brown tumble, and his eyes were brown as well, and bright with insolence. -ASOS, Jaime VIII

Greyjoy

Members of House Greyjoy tend to be taller, with dark hair and eyes:

Balon Greyjoy had always been thin, but now he looked as though the gods had put him in a cauldron and boiled every spare ounce of flesh from his bones, until nothing remained but hair and skin. Bone thin and bone hard he was, with a face that might have been chipped from flint. His eyes were flinty too, black and sharp, but the years and the salt winds had turned his hair the grey of a winter sea, flecked with whitecaps.

and:

"Who shall be king over us?" the priest cried once more, but this time his fierce black eyes found his brother in the crowd.

and:

Nuncle." Asha Greyjoy was tall for a woman, yet she had to stand on her toes to kiss his cheek. "I am pleased to see you at my queensmoot."

and:

Near the end of Haereg's great work you will come to Lord Quellon Greyjoy, the wisest of the men to sit the Seastone Chair since Aegon's Conquest. A huge man, six and a half feet tall,

If interested: Euron's Eyes

Not Great Houses but I was on a roll..

Florent

House Florent is known for their "prominent" ears:

"Of course you are." Davos had known that almost at once. The lad had the prominent ears of a Florent, but the hair, the eyes, the jaw, the cheekbones, those were all Baratheon. -ASOS, Davos II

and:

Those old enough to have known Robert and Renly as children said that the bastard boy had more of their look than Stannis had ever shared; the coal-black hair, the deep blue eyes, the mouth, the jaw, the cheekbones. Only his ears reminded you that his mother had been a Florent. -ASOS, Davos V

Blackwood

Members of House Blackwood tend to be tall and thin:

• Bloodraven

Bloodraven is described in "The Sworn Sword," so I won't repeat that here. He's tall and wiry, but scrawny compared to his magnificent half-brothers. Although a good swordsman, his main weapon is the bow; he has a tall longbow made of weirwood, and fires white weirwood arrows fletched with raven feathers. He is also, by repute, a sorcerer. Sharp features, vaguely sinister. -SSM, Concerning the Great Bastards: 6 April 2004

• Benjicot Blackwood

Tall and slim -Fire and Blood I

• Alysane "Black Aly" Blackwood

Tall and thin -Fire and Blood I

• Royce Blackwood

A tall man and a fine singer -Fire and Blood I

• Tytos Blackwood

At his side stood the Lord Tytos Blackwood, a hard pike of a man with close-cropped salt-and-pepper whiskers and a hook nose. His bright yellow armor was inlaid with jet in elaborate vine-and-leaf patterns, and a cloak sewn from raven feathers draped his thin shoulders. It had been Lord Tytos who led the sortie that plucked her brother from the Lannister camp. -AGOT, Catelyn XI

and:

Lord Tytos Blackwood met him in the outer ward, mounted on a destrier as gaunt as himself. Very tall and very thin, the Lord of Raventree had a hook nose, long hair, and a ragged salt-and-pepper beard that showed more salt than pepper. -ADWD, Jaime I

• Hoster Blackwood

The boy met Jaime by the stables, with a bedroll slung over one shoulder and a bundle of scrolls beneath his arm. He could not have been any older than sixteen, yet he was even taller than his father, almost seven feet of legs and shins and elbows, a gangling, gawky boy with a cowlick. -ADWD, Jaime I

If interested: The Blackwood & Bracken Feud & Coldhands is/was a member of House Blackwood

Dayne

While House Dayne shares some physical similarities with Valyrians, they are not necessarily valyrian and are more likely First Men:

GRRM: I would have to consult my notes to tell you the Dayne arms. Offhand I don't recall. As for the violet eyes . . . look, Elizabeth Taylor has violet eyes, and she's not of Valyrian descent (that I know). Nor is she related to Aegon the Conquerer. Many Swedes have blue eyes, but not all those with blue eyes are Swedes, and not all Swedes have blue eyes. The same confusions exist in the 7 Kingdoms.

Ran: So many banners, I was shooting in the dark. And I was actually arguing that she was a Liz Taylor type. Thanks. :)

George_RR_Martin: If you want to figure out a family's descent, the names are a better clue than the eyes. Stark. Reed. Flint. Tallhart (tall hart). SSM, Event Horizon Chat: 18 March 1999

and according to the Young Dragon, they would have been considered "Stony Dornishmen" and have been described with numerous hair colors:

The stony Dornishmen were the mountain folk, fair of hair and skin, mostly descended from the First Men and the Andals;

If interested: The Dayne Name

Frey

The Freys tend to have a weaselish appearance:

Ser Stevron Frey, Lord Walder's heir, spoke for them. The Freys all looked like weasels; Ser Stevron, past sixty with grandchildren of his own, looked like an especially old and tired weasel, yet he was polite enough. "My lord father has sent me to greet you, and inquire as to who leads this mighty host." -AGOT, Catelyn IX

Reed

While the Reeds appearance is different than that of the average human is Westeros, I don't think they differ from other crannogmen in any respect.

If interested: The "Magics of the Crannogs"

Note: In some cases the wording doesn't necessarily describe the House as a whole, just certain members so we are just guessing in those cases.

TLDR: A list of features that are associated with each of the Great Houses (and some lesser ones as well).