Skip the mantel entirely. : ) You don't see it anywhere, because nobody does it. The mantle is the accent, or part of a surround. You will have all the edges, they will need a pencil trim or a bullnose. It is over think. Pick a tile, and if you need an accent tile ? You really don't or you highlight the fire box. Here's why you DON'T find it........: )

I currently have a gas fireplace with the face of it flush with the wall. I am going to add some stone around the fireplace itself and run it to the ceiling to make it look more astatically pleasing. I currently do not have a mantel but am planning on adding one. Is it best to install the mantel before or after i add the stone tile to the wall? I am going to use something similar to this for the stone...https://www.homedepot.com/p/AIRSTONE-Spring-Creek-Gray-24-in-x-48-in-Textured-Cement-Standard-Rectangle-Primary-Wall-Tiles-8-sq-ft-Each-CLSCFIO/318072375

I wouldnt paint that cover black, its going to stand out more against the white painted hearth, looking at the room on a whole, it seems like a catch all area, I would move the coat rack to the wall the cubby is on to bring some balance to that wall, consider maybe painting the room a warmer tone. eliminate the cubby. and do very simple decor on the mantel. People can really only enjoy the fireplace here as they walk into the room do to the shape of the room there is not much you can do about that. Perhaps the problem isnt the fireplace, but making the room itself more cozy?.

As a temporary thing, I’d just have one thing, solid, centered. Because, there’s this triangle upper shape made by the upper woodwork; the soffit extends past the mantle anyway. Small multiple things just look messy. I like the shape of the metal object because it does have that shape. I’d prefer it darker to pick up the stone more. An almost actual triangle or fat obelisk. But I’d not want you to go out and buy just stuff, or obsess about it. To start, just remove the end objects. Another thing you could try, is a single small art painting, just big enough to be between mantel and soffit and a bit wider, some kind of high- contrast abstract, also centered. You could experiment with using just a piece of paper or poster board.