I would get a nice screen and amp up the mantel decor and art. I like your fireplace very much and can be easily changed when ever you choose just by decor.

I am not sure what is in front of the firebox? That might look better with a different surface,

I'd remove all the little bits and pieces from the mantel, and make a real effort to find that piece of art. If its a working fireplace, how about fire irons?

Go bigger with your mantle decor! Big artwork or mirror, with maybe a tall vase or something. Stick with odd numbers- either 3 or 5 items.

I'm with jmm; get rid of all the small items (except maybe the turtle, because he is almost invisible and he amuses me) and make finding the right artwork a priority.

Okay I guess I’m the overboard queen. (Too much). I put an upper mantel above the fireplace mantel. It’s the vertical wood on the wall. You could use art work or a sculpture would look beautiful. I promised my husband we would use his beloved copper ship. Perhaps something tall on either end to balance out. In our case it was either above the fireplace in the bedroom or over the bed. I didn’t want the “good ship lollipop” to fall on me in the middle of the night. Your fireplace is lovely I’m sure what ever you decide will look great.