Lots of the art in FFH was ripped from various D&D supplements. For instance, the Stonewarden is the picture used in the 3.5 DMG for Red Wizard of Thay prestige class. The mana icons (before they were changed in .25) were all holy symbols from Forgotten Realms. I know there are others I'm forgetting at the moment, but D&D books are one of the many places from which Kael and the team have borrowed their still artwork. Erebus was originally Kael's D&D campaign world, after all...