Much larger art and hung lower the center of the piece should be at eye level when viewed

You don't need to fill it. Just lower what you have already so it's more at eye level. You can replace it with something larger but I don't think you have to.

Here are some examples of gallery walls. You can use family pictures, pictures from travels or buy art. You can build on it over time and like the previous poster said, hang what you have lower to start.

Traditional Living Room · More Info

Oak Ridge · More Info

Upper Canyon Estate 2 · More Info

Thank you all, i was thinking of adding a small photo gallery of the family or bring the current ones down and move them over a bit

ill be adding a small bench w baskets for the shoes and it can be centered

Do a wall gallery. Available at West Elm, Pottery Barn, Home Depot, etc