I really doubt whether this list can be accurate. If you own a huge amount in crypto, then for practical purposes you will try your level best to hide that fact from anyone. Admitting this may attract unwanted attention from the criminals. However, the anonymity will be lost once the holder try to convert his coins to fiat through the exchanges.
Anonymous bitcoin is one of the advantages of crypto money where the owner can hide from the pursuit of the media or does not want to be published, so it is very difficult to find especially holding a press conference. It's very difficult to meet bitcoin millionaires.
But from the media it can be a source of inspiration to become a crypto investor who is always profitable in trading. There is no need to be a millionaire, but getting profit from crypto transactions is consistently a lot of money.
First of all, Bitcoin is not 100% anonymous. All the transactions are logged in the Blockchain. If the authorities want, they can trace your Bitcoin address back to you. In case you want to go for a 100% anonymous crypto-currency, then you should consider Monero, Zcash, Verge or Veil. Also, being anonymous is not that easy as well, if you make your investments in crypto. If the amount is large, then that needs to be shown in the tax returns and almost all the exchanges ask for the KYC information.