Large piece of art. look at greatbigcanvas.com minted.com

Or, Wayfair! They have so many options for large and ways to narrow your search.

A jolt of color on that wall would be nice. If you decide to replace your chandelier, I think black could add some definition to the room.

Your present chandelier will block any artwork you choose.

If you have an art piece you love but it’s too small for the dining room, you can paint a block of color behind it as they’ve done here. To get a sharp line, tape it out and paint the seam the same color as your wall. This will form a seal so your new color will not bleed under the tape.