In Erfworld, the color-codedEvil Overlord's second-in-command is a powerful Croakamancer and far smarter than her boss. However, he has a divine artifact, indulges her hobbies — and she knows how to "arrange it so that he thinks it was his idea."
The prequel book Start of Darkness shows that Xykon was, at one point, the dragon to Redcloak before becoming more powerful and carrying out a rather nasty gambit which involved making Redcloak kill his brother and then ordering him to turn the corpse into a zombie.
Start of Darkness almost serves as a deconstruction of The Dragon, in that it shows what can really happen when the more powerful and evil villain (Xykon) starts out as a tool for the more intelligent but weaker boss (Redcloak).
Also, Sabine serves as Nale's Dragon in the Linear Guild, Crystal is Bozzok's for the Thieves' Guild, and Therkla to Daimyo Kubota.
Note that all three follow the more traditional Dragon pattern of being the brawn; Sabine is a succubus, Therkla is the highest-level character on Kubota's payroll, and Crystal is Bozzok's deadliest assassin, while also managing to be as dumb as rocks.
Elan's father Tarquin has gone into the business of being a Dragon-for-hire after his bid to become an Evil Overlord ended badly. He's currently working for a literal dragon, the Empress of Blood. Since the Empress is a gluttonous moron of a Red Dragon, he's more of a Man Behind the Man in practice.
Arguably, Tsukiko has recently become Co Dragons with Redcloak — while he handles the goblin/hobgoblin Mooks, she's in charge of the Undead. And even if you don't think she qualifies, it should be noted that on at least one occasion, she's announced her goal to fully take Redcloak's position as The Dragon. To the point where she became careless enough to say just that in Redcloak's actual presence. Whereupon he immediately murdered her.
Redcloak and Tsukiko have Dragons themselves — Jirix and the Booted Wight, respectively.
Goblins has had two major Dragons so far — one for each major plot arc. Saral Caine was ("was" being the operative word) Dragon for Dellyn Goblinslayer in the Brassmoon Arc. Grem (until his Heel Face Turn) and Riss were Dragons to Duv in Well of Darkness Arc. Not that Duv really needs a Dragon. She's more than Badass enough on her own...
Sluggy Freelance has had several Dragons in its long run. Most of them (Killum, Aylee, Kusari) have worked for the Hereti Corporation's Omniscient Council of Vagueness. Other notables include Lord Grater (Dragon to Zorgon Gala in the Punyverse arc) and Nash Straw (Dragon to Dastard Dickly in the "Phoenix Rising" arc) and Lord Horribus (Dragon to the Demon King in the Dimension of Pain stories).
Karnak from Dominic Deegan seems to have acquired a Dragon himself, in the form of Siegfried. He doesn't seem to be particularly loyal to Karnak, though, as Karnak appears to have some kind of hold over him, and even then has to smack him around a bit to make him do his bidding.
Also, Helixa seemed to be The Dragon to the leaders of The Chosen, first serving Raf MaLiksh, then to Caylin Bren (though it might've been the other way around for the latter, considering Helixa was pretty much second-in-command to MaLiksh himself before his death). She could also be viewed as The Dragon to Celesto Morgan after he joined the organization as well.
The Feline Emperor from Blade of Toshubi has his advisor, Toh, who himself has his own dragon in Lamika.
Much like each season having its own Big Bad, half of the seasons have its own Dragon in Ansem Retort:
Season 1: Ansem to the FOX president. He's later a Dragon Ascendant.
Season 3: Vexen to Ansem.
Season 4: a turncoat Larxene to Xemnas
Season 6: a turncoat Red XIII to Xemnas, Sho to Belle.
In Voodoo Walrus one gets the feeling that Shmeerm use to play this role to the former Big Bad Cyradwee. Now he seems to be playing Dragon some someone else though.
In Minion Comics Mr. Magnum plays the role of Dragon to Von Gernsbach, recruiting his minions and overseeing operations.
