Breakdown/Knock Out
I see their relationship as a rare instance of mutual respect and almost-unconditional loyalty among the Decepticon ranks. Knock Out never seems to have a harsh word for Breakdown and carries out (what he perceives to be) Breakdown’s wishes to truly gruesome lengths; Breakdown gets drawn into Knock Out’s schemes despite his better instincts and follows his orders without question. They finish each other’s sentences, riff off each other’s terrible jokes, egg each other on into increasingly dastardly deeds, and seem to accept each other as they are, flaws and all. And of course, there’s that rotary buffing. Breakdown and Knock Out very much feel like an old married couple (though I wouldn’t be opposed to some get-together fic if that’s what you wanted to write). They’d kill for each other without a moment’s hesitation, and they probably have.

It’s not all sweetness and light, though: I’d like to see some conflict between them. Perhaps Breakdown shows flickers of a conscience and Knock Out has none; perhaps Knock Out harvests some poor sap’s organs for Breakdown’s benefit. I’d also like to see exploration of their difference in rank and (apparent) social class. How free is Breakdown to say no to Knock Out? Is their relationship taboo or hidden? (Was it legal before the war?) In an AU in which Breakdown lives, do they clash?

I’d also love to see any of the following: mechpreg or egg-laying (prefer pregnant Breakdown); emphasis on their vastly unequal size and strength/different biology; pre-war backstory; post-war fallout; canon-typical Team Rocket shenanigans; mutual devotion contrasted with cheerful brutality to everyone else; one going on a roaring rampage of revenge when the other is hurt; tender or gruff hurt/comfort; and, of course, some tender bathing and maintenance.

Knock Out/Starscream

I see them as fair-weather friends who’d turn on each other at the drop of a hat yet are surprised to be themselves betrayed. Starscream treats Knock Out as a punching bag; under a thin veneer of politeness, Knock Out gives as good as he gets. Starscream needs a sympathetic audience; Knock Out is a pathologically insubordinate smartass. Starscream has no time for anyone but himself; neither does Knock Out. There’s no situation that they can’t bungle. Knock Out was probably right when he said that Starscream would fire him out the airlock at the first opportunity--and he’s rude--and Starscream would find a way to make it Knock Out’s fault. And I love Starscream’s contempt for Knock Out’s alt.

I’m intrigued by the suggestion in Knock Out’s introductory episode that Starscream knew of Knock Out before the show. Did they have a past early in the war? I’d also like to see them reunited by some postwar twist of politics. Or some good old-fashioned canon-typical shenanigans would be great: perhaps Knock Out does some malpractice under the guise of routine medical care, or Starscream sends Knock Out on a truly miserable mission. If you’d like to write sex, this would be a good pairing for the crappiest sex you can imagine.

Bulkhead & Miko Nakadai

Their relationship was one of the most human, sweet things about the canon for me: while Bulkhead starts the show seeing Miko as a fragile, alien being to protect, and Miko just sees a big alien robot from space (straight out of a monster movie), they're almost immediately bonded together as individuals. The first season in particular puts a lot of focus on how much fun they have together. One gets the sense Bulkhead doesn't get to have a lot of fun during an apocalyptic civil war.

This would be a good relationship for canon-typical adventures set during the canon itself or well afterward. I'd like to see what the future holds for Miko: I can't see her settling down in an ordinary life after the war's end. Perhaps she struggles to adapt to a life where she's not being shot at regularly. Perhaps she makes a career in alien investigations for Unit: E. (Does she return to Japan? Does she travel the world?) Maybe she resents Bulkhead for leaving; maybe she comes after him, years or even decades later, as human space travel technology takes off (with a little help from Ratchet?).

If you want to go with something darker, being around Bulkhead is endangering Miko--she really is a squishy, breakable little human, and she's a teenager thrown into war who learns to kill and sees her big lovable robot buddy nearly killed several times. Bulkhead does his best to protect her, but his best isn't--cannot be--good enough. I'd love a fic that explored this, as well as how responsible Miko might feel for Bulkhead's well-being.

I'd also like some focus on Bulkhead's interiority: on his inferiority complex, on his willingness to let a helpless enemy die (until Miko reminds him of the chance of a rematch), on his fear of becoming useless after an injury and his anger toward Smokescreen. I'd love to see someone explore the darker sides of his character here.

General Likes:

-Dystopian settings, including depictions of political repression and fantasy bigotry
-Body horror, including surgical horror, organ harvesting, or mutation into something horrifying
-Villain protagonists being repulsive

-Frametypes having different physiological needs

-Focus on the alienness of Cybertronians

-Robot whump

-Ideological conflicts, especially irreconcilable ones
-Big, teeming, bizarre cities
-Canon-typical adventures or scenes from a longer adventure
-Mad science, the more unethical the better
-Focus on daily life in fantastical settings

-Corruption arcs or descent into evil
-Relationships in which both characters are equally formidable in different ways
-Bathing
-Dark comedy
-Bad puns

-Time loops, especially if they make everything worse