I think litecoin is good, due to the low transfer fees (and as such I use it to sell my steem). Tether might actually work as a spendable cryptocurrency, as it is pegged to the dollar. Cardano has potential too (for decentralized apps: something we really need, as most apps today run on a central server – and the company can do anything to them without user consent). Tron has similar potential, but the decentralized web doesn't need cryptocurrency tokens – try IFPS or ZeroNet (no cryptos there) – unless you're trying to privatise it. All in all, litecoin is the most established, and as such the best (after steem).