My picks from your list:
Airswap - Decentralized exchanges are the next big thing in 2018 and beyond. I would get in on all of theses types of investments and we'll see which one flies. This one happens to have great backing, including Novogratz as an adviser.
Substratum - If this thing works like everyone hopes it does, forget about it.
Ethos and Salt will do fine, but high market caps already.
Nav, Spectre, Onion, good coins, highly speculative, big potential returns.
These are good options. Privacy coins are gonna be big just like john mcafee said. As governements begin their crackdown with regulation traders will simply go underground with anonymous coins like xspec and onion. Grab some now while the market cap is low