This is a question you need to find answers to yourself, no one will give you the right answers but only different suggestions, you already have top altcoins like ETH, LTC , Zcash etc so you know what's good and what's bad, do your own research and make your choice, I can drop the names of altcoins I'm holding too if that will help
1. Eth
2. BNB
3. ETN
4. ESH
5. KCS
6. VEIL
I am interested in VEIL. Did a little bit of research on this coin and almost a year ago, I invested a small amount in to it (around $100). But the big problem with VEIL is it's storage. It requires a lot of bandwidth and disk space. I grew frustrated after a few weeks and uninstalled the wallet form my laptop. They need to come up with a Lite wallet or a mini wallet.