Check Etsy. Can find some high quality buttons there too usually priced a lot better. Usually some combination of 3D-Printed and silicone-cast resin so lots of glossy options but I have seen matte ones as well. $20-30 range (USD)
They're pricey for sure, but they have a lot of unique options and I imagine the production numbers are pretty low, so high prices are to be expected unfortunately.
The metal buttons in particular can have the surface finished in different ways to match your desired texture.