Actually, the year that I failed to post a fic for the prompt, I ended up writing something for it that was waaaay too long to qualify. But, like you said, it refused to be trimmed down. It deserved to live, so I let it ;)

*cheers "Agent Carter, Agent Carter!"*

I usually let the picture decide which fandom I'll write in. I actively write in half a dozen fandoms, so I have the benefit of choice. For example, this year my prompt finally said Forever even though I'm not entirely comfortable with that one. Then I wrote a Criminal Minds one afterwards because it just popped into my head fully formed.