Is Ethereum second?
If so wich Cryptocurrency Will be third, 4th. 5th.??
What You think wich coins are competing with Ethereum?
I Think Ethereum and Bitcoin are number one!
3rd. I Think its a BCH.
You can always look at CMC or coinmarketcap.com to see what coins are currently competing. Although it is a paid site by managing and changing volumes of different exchange sites, it is still a good statistics for cryptocurrency. I remember that TRX made it to top 3 at some time. It was the time when TRX was from 500 sat to 2000 sat.