As of RIGHT NOW, probably Monero or Ravencoin - but that has ALREADY changed this year, and is likely to change a FEW MORE times - and it also ...
source https://www.google.com/url?rct=j&sa=t&url=https://www.quora.com/Which-is-the-best-cryptocurrency-for-mining-in-2019&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNGI1CnsRg0vjGPAxvijaPFEPYSqIA
