The soft drawstring bag that came with your Oakleys (NB other brands may be available…)
That’s what I used, after I broke the zip on my expensive Oakley wallet cramming too much loose change into it.
I’ve worn holes through four sunglasses bags so far, and I now use a little leather drawstring bag that I bought from a bloke who has a market stall in town; he sells ex-army gear, and he does bushcraft stuff too, which includes leather bags for carrying flints and fire strikers, tinder, and other bits and bobs.
Nice thick leather, and not to big to carry in a back pocket. Looks like the ball bag, but a bit smaller.