@Gargron Answer: you can't keep track of all of them. Pick one or a small number that are of particular interest.

Maybe one of them has some interesting characteristics; maybe another is seeing uptake by some industry that interests you; maybe another is tackling sky-high transaction fees; maybe one more is based on a sort of escrow to make transactions less risky. So you would choose from a smaller set of #cryptocurrencies instead of whichever one currently appears on the first page of the cryptocurrency exchange rate trackers and the newspapers.