User blog comment:Greater good/Targaryen kings/@comment-94.64.133.235-20150708053416

My guess:

First: Aegon I.

Second: Wears the simple crown of Aegon III, so I suppose he's Aegon III.

Third: Daeron I, who succeeded Aegon III and wore Aegon I's crown (the crown of the first and third king are the same, if you notice).

Fourth: Clearly Baelor.

Fifth: Wears the crown of Maekar I, and is holding a sword, I'll go with Makear I.

Sixth: Wears the crown of Aegon III, and is after Maekar I, so he's Aegon V.