Queen Sumana of the Arcadians
From Filmation's Season 1 Episode 39 Trouble in Arcadia: Queen Sumana rules the beautiful hidden city of Arcadia, where men are kept underground as slaves to mine arcalite, the mineral that fuels the invisible "power dome" force field that protects the city from outsiders, and only women are citizens allowed above ground.
I think her character looks great, and doesn't appear to be a difficult figure: a regular female body repaint, and a rare opportunity to reuse Queen Marlena's dress. I think the only new parts needed would be a new head and her characteristic dress sleeve extensions.
I think her throne is awesome too; too bad diorama accessories are out of the question.
A 2-pack of her together with Ananda (the slave master—the only man admitted above ground—and her future husband and king) could be a nice idea:
Regular Arcadians [see attachments] could make for a good and easy "army/population builder" 2-pack: a citizen/soldier woman and a slave miner (with two heads each for variation). And, just to complete the picture of characters that appear in this episode, there's also the Arcadian mistress of arms, who almost melted down He-Man's sword at Arcadia's foundry! Lastly, I've included a shot of an Arcadian airship, which has a simple design that, nonetheless, I've always thought looks pretty nice (again, too bad vehicles are also out of the question).