A while ago, Amok asked GRRM for descriptions for some of the important Targaryens that never ruled, and as such weren’t included among the portraits in the artbook. GRRM recently replied that he was too busy to supply descriptions for them all at this time, but that he would try to send a some now and then. He did, however, send descriptions for two of them: Visenya and Rhaenys, Aegon the Conqueror’s sisters and wives.
You will find the descriptions on Amok’s forum and the portraits in his artbook gallery. Amok has also put up one other new painting in his main gallery, showing the three Targaryen siblings and their dragons on the Field of Fire.