I've sunk way too many hours into reading Cyclonus/Tailgate fics, and the ones that stick with me aren't always the obvious ones. Everyone writes about the 'grumpy one is soft for the sunshine one' trope, which is great, but it gets surface-level fast. The really good writers dig into the inherent tragedy of their dynamic—Cyclonus has lived for millions of years, carrying all that weight and loss, while Tailgate's entire existence up to meeting the Lost Light is, like, a blip. Exploring that gap, the sheer impossibility of their timelines ever truly aligning, makes for such bittersweet material. Does Tailgate feel inadequate? Does Cyclonus get frustrated trying to explain things Tailgate can't possibly comprehend? A fic that leaned into that, where their affection is constantly bumping against this massive, silent wall of time, absolutely wrecked me.
Also, post-canon fics where they've settled into something domestic and quiet, but Cyc's old war instincts keep flaring up over nothing, and Tailgate has to gently talk him down. Or the reverse—Tailgate getting bored with peace and accidentally stumbling into trouble, with Cyclonus having to both rescue him and pretend he wasn't worried sick. Their dynamic just has so many layers beyond 'big guy small guy'. The best tropes use their history to complicate the present.