In order of most favored:
NEO: (Personal Fav). Huge Chinese Crypto industry. Working with the government. Smart Contracts. Also GAS!
ETH: 2nd Market cap. First at smart contracts. Reliable. But they are falling behind hence second.
XRP: Riding the hype. Big company. Well organized. Centralized
Any other ones you would recommend (Preferably about 20 top market cap) ?
i think besides the three coins above
maybe IOTA can be a good options mate, why ? just read this article below and you will find the answer
https://www.reuters.com/article/us-crypto-currencies-jaguar/jaguar-land-rover-planning-to-allow-helpful-car-drivers-to-earn-cryptocurrency-idUSKCN1S40UD
regards