I think if you mention the king about coins that are worth mentioning is BTC and the second one is ETH. even though both of them have been decreasing for several months in terms of value prices with the emergence of new coins listed in the exchange market, a number of days have begun to change towards increasing prices.
For sure, the king of the coins is bitcoin .. for now. Point is, when its about altcoins, ETH really is pretty much in the front. Point is, why do you forget about IOTA, DASH and XMR?
In my opinion, IOTA is a lot more scalable, therefore a lot more useful in the future. Dash has pretty much most things ADA wants to implement (in the future) already there lying around and Monero is just the only real privacy coin.