Tons! I have a half finished novel in which one of my alters is the main character. It was quite strange, really, how I learned to communicate with him through the writing without even knowing it. I could probably talk for hours about all that! I knew he was a part of me, but dang! I didn't realize he was a PART of me. Until he started talking to me. I should have realized, I mean, looking back at how I was interacting with him internally, it was only strong denial that kept me from putting it all together.
I also have short stories I've written that are about other alters, and some of these I started before I knew about DID. All the contents of my subconscious are in those pages, most of it in symbolic form. It's been a way for me to handle those things in a less direct way than remembering, and I'm very grateful for that. I've also done quite a bit of art like that, and sometimes it's one of the others producing or driving the artwork. I've considered sharing some of the artwork but really it's all very triggery.

Have you had a new alter form in adulthood?