If you’re saying being used together, these coins are totally different and they are competing with each other. But let’s say in terms of being used for transactions, which other coins are going to be as popular as Bitcoin, we all know for sure that top on the list are Ethereum and Litecoin, these ones are very popular and there are already lots of people who make use of them.

You can hardly see anyone making use of any other altcoins for transactions apart from these two. Another coin which I have seen being used is Ripple, but only once. So, I will say that Ethereum and Litecoin are on the top list of coins that will be used alongside Bitcoin.