Short list of my top 3 coins that will see the biggest gains by 2020:
1. Matrix AI Network
2. NEO
3. EOS
I agree with your opinion. these three altcoins do have very good potential for future investment, but you seem to forget ethereum. This altcoin has the best potential in the future
Maybe ethereum is just like a stable growth coin so it may not give much growth rate like other altcoins and also the ethereum availability can be the reason why OP doesn't add it to his list but I choose ethereum as well if my investment is going to be in years may not it give the huge profits but we can reduce the risk factors.