For top ten altcoins you can go to coinmarketcap and search the top 10 altcoins but My favourite  First is Ether because Ethereum is an open software platform based on blockchain technology that enables developers to build and deploy decentralized applications.And now a days you can see many many ICO coming with Ethereum platform.Second is Bitcoin, because bitcoin is the mother currency of all coin and its ever green currency,and the third in this list is Steller, Fourth is Cardano, and the last the fifth is NEO.And the other five is  GVT, IOTA, RIPPLE, DASH and POWR