Knitting ideas/patterns

First time posting on and also joining a forum, hoping this isn't too bad!

I've been knitting a sweater for a while, on and off, but I really want to finish it. The base of the sweater is black, and I was planning to go for a Doctor Who theme, but now I'm not so sure. I have brown and dark green yarns, and I'm thinking of going in and doing little details around the neckline, sleeves, and bottom ribbing, to make it feel more mystical. I probably shouldn't have done a black sweater, but it's what I have to work with.

Any ideas of little details I could potentially put into it later? And if anyone is truly interested in what I'm doing, then once I'm done I'll post a picture of it here!