Many Armorials containing Arthurian Heraldry, including most of those referenced by Michel Pastoureau can be found online. Here are some examples:
Noms, armes et blasons des chevaliers de la Table Ronde, The Morgan Library & Museum, MS M 16, published ca. 1500
Works on knighthood and tournaments, Harvard Library, MS Typ 131, published ca. 1470
Armorial manuscrit des chevaliers de la Table Ronde, Bibliothèque Municipale de Lille, MS 329, published 1401-1500?
Blasons de la Table ronde, Bibliothèque nationale de France, MS 1435, published 1501-1600
Armoriaux de la table ronde, Bibliothèque nationale de France, MS 1436, published 1525-1545
Armorial des chevaliers de la Table ronde, Bibliothèque nationale de France, MS 1437, published 1485-1495
Le Blason des Armoiries de Jérôme de Bara, Bibliothèque nationale de France, V-4345, published 1628
Armorial de la Table ronde, Bibliothèque nationale de France, MS 4976, published 1490-1500
Ce sunt les noms, armes et blasons des chevaliers companions de la Table ronde au tamps du roy Artus et insi qu'ils estoyent assis, au comencemant de la grant queste du saint Greal, a la dite Table ronde, Bibliothèque nationale de France, MS 5024, published 1401-1500
La devise des armes des chevaliers de la Table-Ronde, Bibliothèque nationale de France, RES-Y2-1298
Les noms, armes et blasons des chevaliers et compaignons de la Table ronde, au temps que ils jurèrent la Queste du Sainct Graal, Bibliothèque nationale de France, MS 12597, published 1401-1500
Traité de blason, Bibliothèque nationale de France, MS 14357, published 1401-1500 https://commons.wikimedia.org/wiki/File:Trait%C3%A9_du_blason_MS14357_BnF.djvu?uselang=fr
La devise des armes des chevaliers de la Table ronde, Bibliothèque de Rennes, L-2012-0017890, published 1525
The illustrations in the Armorial's from the Morgan, MS 1437 and MS 4976 are, I think, particularly good.
Many more armorial's containing attributed arms for the Arthurian knights, from the late medieval period, are in museums and private collections around the world. If anyone comes accross additional on line Armorial's, please send me a link
Occasionally armorial's come up for auction, such as this one from Christies in 2010. The photographs to illustrate the auction can also be useful.
The tradition of publishing Armorial's containing the arms for King Arthurs knights continues to this day.
In Les Armoiries des Chevaliers de la Table Ronde Freddy Sibileau has combined information from Michel Pastoureau's work with a more detailed study of the medieval Arthurian romances. I am not sure that I agree with all his conjectures (more on this later), but it is a very comprehensive and useful study.
Building on this, in the blog Los Caballeros de la Tabla Redonda the author has taken Michel Pastoureau's and Freddy Sibileau's work and illustrated the arms for each knight.
