In Manchester Lost, this ends up having an interesting twist. Crowley has a shoulder angel and demon represented as Inner Aziraphale and Inner Hastur. Aziraphale has an Inner Crowley and Inner Raphael. Both sets are hilarious.
Played with in a Misfitverse (longrunning X-Men Evolution / G.I. Joe crossover) story. Forge's experimental Shrink Ray accidentally de-bigulates several of the adults - including Beast and Angel, who end up climbing onto Kitty's shoulders and arguing about what to watch on TV.
Here we see K-On's Tsumugi get advice from her angel (Yui) and devil (Ritsu) in an awkward situation.
In Kyon: Big Damn Hero, Achakura and Kuyou transform into these tempoarily, but neither of them quite get Black and White Morality.
Calvin and Susie have an argument in In Love and War. In responce, Spacemann Spiff and the Dictator-for-Life appear. Shortly afterwords, a Hobbes and pirate Hobbes appear as well. As it turns out, the entire shoulder angel secquence was All Just a Dream.
In the Dark World of the Pony POV Series, the Nameless Passenger and the Benevolent Interloper serve as this to Twilight. Both speak to her, the former trying to turn her against her friends and focus on her revenge on Discord, the latter reminding her to stand by her friends and not make the battle with Discord be about vengeance. The Passenger turns out to be the Bigger Bad of the Dark World Series and Twilight's own potential future self.
During the Hot Springs Episode of Tengen Toppa Gurren Solvernia, they try to talk to Kamina. The Bad Angel argues that Kamina should see the girls' side, but the Good Angel tells him to not do it, because Nia is among. Then the Bad Angel reminds that Nia shouldn't be there anymore, and thus the Good Angel tells Kamina to continue with his plan.
Played in a literal sense in Ah!Archfall!, in that Jago actually has an angel AND a devil
