of course cryptocurrency will remain forever, because now many companies are collaborating with cryptocurrency to develop their companies or as a payment method, one of which is Tesla, which accepts payments using Bitcoin.
Litecoin, Bitcoin, and possibly xrp.
Litecoin is much faster, cheaper to send, way undervalued, and will become scarce as institutions buy it up. It also is easier to evolve with a collaborating development team and foundation.
Bitcoin, due to being the first one and recognizable, being used as a store of value as insecurity with fiat increases, etc.
XRP because if it is adopted by banks, despite having billions of coins, could become a mainstream tool for banks, etc.
I think you can add Binance too, because now Binance is already making a great progress, that is :
1. Binance has a very large exchange, because the volume on Binance exchange is very high;
2. Binance has a smart chain (blockchain), so that companies or other cryptocurrency projects can already use the blockchain from Binance (BSC).
That's why I believe Binance has a very good potential to be used as a long-term investment, because the price of Binance will definitely increase very high and give us a big profit.