I’d take away the two framed (is one a mirror?) things. Done.

It depends on what the rest of the room looks like stylewise. What furnishings do you have? Do they have wood finishes? More photos are needed to give you best advice.

the empty frame is just sitting their, I was going to put a picture on it, but not sure whats best. maybe just the K print and any other ideas what to do with the rest of the manel? the room is pretty neutural color, beige, sectional/ photos of family above couch. pretty simple...

So you were asking about mantel "decor," and not the mantel itself? I misunderstood. Again, a look at the rest of the room would help some of us suggest art work and other items in a palette from your furnishings, rug, pillows, etc. The big lettr "K" isn't as interesting as an art work might be.

Here are some framed art prints from Society6, which can be ordered in different sizes. An abstract landscape or pattErn over a fireplace with a wood frame matching the mantel would connect them.

To make your fireplace more inviting add a basket of chunky logs on the hearth and in the firebox. Right now, it's just a black box.

Its a gas firep;lace

One nice piece of artwork and nothing else is my recommendation. Just looks too busy and doesn't add to an overall look. My opinion only!