Something you're just good at with minimal effort and/or you learned much more quickly than average.
For me, it's paper snowflakes. My brain just seems to effortlessly figure out what cuts to make to the paper wedge to make it turn out exactly how I want it. Largely useless, but good fun and was a much-needed ego boost when I was a kid :]
My ability to whip a story up at the spot is pretty damn good. I run Dungeons and Dragons in a homebrewed world, and a good part of it is made up on the spot. While doing this, I always make sure to keep consistency.
The only thing I'm lacking is long monologues.... That is hard to just make up
That's a fantastic talent. Creativity is one thing but quick improvisational creativity is a whole other level
For monologues: do you do ok improv-ing dialogues? If so maybe you could trick your brain by thinking about how a monologuing character is kind of having a dialogue with different parts of themself