In my opinion it will be ethereum, coin second in market; Next is Litecoin, a bitcoin-inspired digital coin, and at the moment it is one of the most prominent Altcoins among existing digital coin. This is first seen as a competition with bitcoin because it takes 2.5 minutes to create a block, compared to bitcoin takes 10 minutes. In addition to speed, Litecoin can also handle higher transaction volumes, and faster generated blocks mean fewer opportunities for attacks than twice. Finally, Bitcoin Cash, co-detached from August from Bitcoin with the original idea to increase the size of the block and allow for more trades. Bitcoin Cash increases the block size to 8 MB and also removes SegWit to increase the number of transactions. Supporters believe that Bitcoin money will soon be able to compete with the transaction volume of Visa or PayPal. Right now, it's in a stable position and is expected to climb higher in value.