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) ?
XRP is a good one to invest, just because still a alternative coin on 3rd place in coinmarketcap , this is the next era of banking. i can recommended to you ziliqa coin too. its in the top 50 , its a sharding solution , great team is there to backup.