We have a fireplace that is similar, and for years, I would switch out the decor according to the season...
Easter/Spring & Summer - White Orchids and Green Topiary Plants
Fall/Thanksgiving - Ceramic Pumpkins and a Burgandy, Gold, and Orange Arrangement
Christmas - Silver and Gold Reindeer and a Nativity Scene
January thru March - Ice Blue and Silver Candlesticks and Candles
2020... Lost my motivation - The Orchids and Topiaries have been up ever since
I've just been switching out the Seasonal Wreath on the front door, and that's been the extent of my "decorations" since then. 