Where to buy 1-2 oversized stepping stones

Hi r/Houston! I’m in a pickle. I’m looking for 1-2 oversized stepping stones (think 30+ inches long, ~18 inches wide, either 1 stone that is 5 inches tall or 2 stacked that get to 5 inches) and I’m having trouble finding them. I’ve checked out the Lowes and Home Depot in the heights, I’ve stopped by a few nurserys in the area, and when I look at stone supply shops they are selling in large bulk numbers that I don’t need.

Does anyone have a go to stone place that will sell in single stone increments and might have what I’m looking for?