Bitcoin Fog did pretty well during its run. It mixed Bitcoin from at least two huge thefts. At least one of them generated a huge Reddit crowd-sourced tracking effort. And as far as I know, nothing was ever tracked.

I do get that Monero is ~anonymous by design.

But then, how does one buy it anonymously? All I see are exchanges that implement KYC. Using bank transfers and credit/debit cards. Are there any cash by mail exchanges? Or even local meatspace exchanging?