Tropic Eden Reefflakes Grand Select - 4.5mm is about the bigest you are going to find that’s marketed for sand floor substrate. It’s big enough that it doesn’t blow around too much (I run 3X tunze 6105) but fine enough that my diamond back goby has been doing fine for 2 years in it.
I really like Carib Sea Natural Reef, has a nice mix of grain sizes, looks natural hehe and doesn’t blow around. Got min at Petco and they Match their web price like $22.