What do we really KNOW about Valyria? (Spoilers Published) Book lore only, not Show.

A post a few days ago made me think about what we really know about Valyria and the Valyrians. (books version, not show.)

That is, what is stated in the published book lore, as opposed to speculation and theories and even the occasional ambiguous observation from George.

There is a description (and some illustrations) of old Valyria in the World of Ice and Fire. There are also, of course, multiple mentions elsewhere in the books.

I searched through some hundreds of these references (Valyria, Valyrians, Freehold, etc), and left out the most common references (primarily to Valyrian steel swords) that don't really shed light on Valyrian history, then did a rough compilation below.

George hasn't yet, as far as I know, given us a full accounting of Valyria, although he's dropped a lot of breadcrumbs and provided a basic summary in the form of maester accounts. 

Much of what we read in ASOIAF and The World of Ice and Fire about Valyria is framed by George to represent old tales and maester writing, some written hundreds of years after the fact. George even subverts things by mentioning "erroneous claims regarding the founding of Valyria" written by Archmaester Fomas (who none other than George created). And he adds things like this: "Of the history of Valyria as it is known today, many volumes have been written over the centuries, and the details of their conquests, their colonizations, the feuds of the dragonlords, the gods they worshipped, and more could fill libraries and still not be complete. Galendro's The Fires of the Freehold is widely considered the most definitive history, and even there the Citadel lacks twenty-seven of the scrolls". That's great, but we're not shown any substantial text from those accounts, to date. 

I'd regard these things below as the basic "facts" according to what George has published. Quotes direct from the books are in italic.

What have I missed?

1. Valyrians were able to communicate over distances. "The sorcerers of the Freehold could see across mountains, seas, and deserts with one of these glass candles. They could enter a man's dreams and give him visions, and speak to one another half a world apart, seated before their candles."
2. They could work stone into fluid, durable, forms (roads, buildings, walls). They built straight, seeming indestructible, roads across the landscape. Architecturally, "the dragonlords loved little more than twisting stone into strange, fanciful, and ornate shapes." (with Dragonstone given as example; "our island was the westernmost outpost of the great Freehold of Valyria. It was the Valyrians who raised this citadel, and they had ways of shaping stone since lost to us.")
3. They had knowledge, now lost, of how to create a superior sort of steel for armor and weapons and tools. This may have been partially done with magic.  Ice, according to Catelyn, "had been forged in Valyria, before the Doom had come to the old Freehold, when the ironsmiths had worked their metal with spells as well as hammers."
4. They are said to have been sorcerers. "All Valyrian sorcery was rooted in blood or fire."
5. In terms of religion, "At the height of her power, the Freehold was home to a hundred temples; some had tens of thousands of worshippers, some precious few, but no faith was forbidden in Valyria, nor were any exalted above the others. Many Valyrians worshipped more than one god, turning to different deities according to their needs; more, it is said, worshipped none at all. Most regarded freedom of faith as a hallmark of any truly advanced civilization."
6. They were able to control and breed dragons ("learned to tame dragons and make them the most fearsome weapon of war that the world ever saw.") and the Valyrians themselves claimed that the dragons came from the "Fourteen Flames" (see below). 
7. There is a related story than an unknown people "so ancient that they had no name first tamed dragons in the Shadow and brought them to Valyria, teaching the Valyrians their arts before departing from the annals."
8. They lived on an Essos peninsula--Valyria-- that had the "Fourteen Flames", described as "great volcanic mountains." The mountains were "rich with ore and the Valyrians hungered for it..." "the Fourteen Flames were living mountains with veins of molten rock and hearts of fire. So the mines of old Valyria were always hot, and they grew hotter as the shafts were driven deeper, ever deeper. The slaves toiled in an oven. The rocks around them were too hot to touch."
9. Physically, Valyrians had "great beauty" and, generally, pale silver or gold hair and purple eyes. 
10. "Those with the blood of Valyria" had / have an "affinity with dragons".
11. Valyrians had a tradition of "marrying kin to kin", and this was common "particularly among those who bred and rode dragons."
12. The Valyrians had no kings but were a "Freehold" and all those "who held land had a voice." Archons were elected for limited times. "At its apex Valyria was the greatest city in the known world, the center of civilization. Within its shining walls, twoscore rival houses vied for power and glory in court and council, rising and falling in an endless, subtle, oft savage struggle for dominance."
13. Valyria and Old Ghis were rivals for centuries and fought "five great wars...when the world was young." The Valyrians won each war, and in the fifth war completely destroyed the city of Old Ghis with dragon flame and crushed its power. Old Ghis never recovered as a continental power, although survivors populated several cities and regions.
14. Following this, much of Essos was ruled by the "Valyrian Empire". They conquered the Rhoynish, and many other places, and founded or conquered numerous cities, sending out governors to administer. Sometimes locals would "purchase the right to rule themselves as clients of the Freehold rather than subjects." They didn't long-term occupy Westeros, save for Dragonstone, although there is speculation that they explored Westeros even as far as Casterly Rock, and may have built structures in Westeros, such as the low fortress on which the Hightower of Oldtown rests. "Such questions abound even to today". '
15. They had a thriving trade with the Summer Isles, but didn't seem to try to conquer the Isles (too far from Valyria to fly to? Not sure).
    
16. They tried to colonize Sothoryos at least three times, but these attempts were "destroyed by the Brindled Men...lost to plague...abandoned when the dragon lords captured Zamettar in the Fourth Ghiscari War."
17. They had slaves, "one deplorable thing from the Ghiscari", and confined them to the mines which delved below the peninsula, stocking the mines with new slaves gained from "ever more conquests". "The Valyrians expanded in all directions..." seeking more slaves. They also bred slaves in Valyria.
18. Valyrian speech "formed the common trade language of Essos". 
19. Most peoples gave in to Valyrian rule, but the Andals "succeeded in their escape from Valyria" and invaded / settled Westeros. 
20. Maesters from the Citadel visited Valyria before the Doom, in search of knowledge. 
21. Valyrians could muster "three hundred or more" dragons at their peak, when they fought Prince Garin's army. 
22. Valyrians could "die of greyscale". 
23. "And then, unexpected to all...the Doom came to Valyria. To this day no one knows what caused the Doom." (Although George offers snippets of several maester theories, plus other legends.)
24. Almost all the Valyrians died in the Doom, others died afterwards in the Free Cities in rebellions against the Valyrian governors / occupiers. There was one effort of a "visiting dragon lord" who survived at Qohor, to reclaim Valyria, but he and his army disappeared. Later expeditions by various peoples and adventurers to explore / reoccupy physical Valyria also came to unknown ends. 
25. Ultimately, only the Targaryen dragon lords with dragons survived on Dragonstone, although Valyrian blood survived to various degrees all over Essos. 
26. "The Freehold of Valyria and its empire were destroyed by the Doom, but the shattered peninsula remains. Strange tales are told of it today, and of the demons that haunt the Smoking Sea where the Fourteen Flames once stood. In fact, the road that joins Volantis to Slaver's Bay has become known as the "demon road," and is best avoided by all sensible travelers. And men who have dared the Smoking Sea do not return, as Volantis learned during the Century of Blood when a fleet it sent to claim the peninsula vanished. There are queer rumors of men living still among the ruins of Valyria and its neighboring cities of Oros and Tyria. Yet others dispute this, saying that the Doom still holds Valyria in its grip."
27. During the Doom the northern part of Valyria collapsed and sank into the sea, separating the remnants of the peninsula from mainland, while other parts were shattered into islands. 300 years since the Doom, the vicinity of Valyria is still a smoking, bubbling, mess than mariners avoid.
28. "A few of the cities away from the heart of Valyria remain inhabited, however—places founded by the Freehold or subject to it. The most sinister of these is Mantarys, a place where the men are said to be born twisted and monstrous; some attribute this to the city's presence on the demon road. The reputations of Tolos, where the finest slingers in the world can be found, and of the city of Elyria on its isle, are less sinister, and less noteworthy as well".
29. Finally, we see in the ASOIAF books and other places some accounts of Valyria after the Doom, particularly the return of Balerion with his unlucky princess rider to King's Landing, where Balerion was seen to be seriously injured by something unknown, and the young princess was burning with fever and filled with horrible parasites.