I would go for coins that have solid roadmaps that are being hit.
Coins such as ADA should increase dramatically in 2 years time as they become more mainstream, and are seen as a "V3 Blockchain" by many.
NEO is also a good one to hold as you have mentioned, you get GAS as your interest which is a great benefit.
Cardano (ADA) is a good project in Assia. It has a good potential. I don't agree with neo. It's good to stake some gas but itself it's not that amazing. Ethereum is much better than neo. I can also say monero is a good coin for holding.