Okay, here goes my choice of altcoins below $1 already listed on exchanges and coinmarketcap (which I have looked through. There can be many other good project I've not heard about)
1. Electroneum - They are in top 100 but comes in just 2 cents. Though had some trouble initially, they are a working, mineable cryptonight.
2. Ripple - 67 cents Seriously, I don't like them, but they have an active team with contacts to high level of people in banks. They can make a differnce.
3. Thekey - one and a half cent, they are on a steady ride with a steady project.
4. Docademic (MTC) - 21 cent, they actually showcased their hardware, app and seem to have real contact with doctors and hospitals.
5. Zeepin (ZPT) - 6 and a half cent They are too building their own blockchain, experienced group of chinese.
I agree with this.
for docademic (MTC) I participated from the beginning of the pre-sale token, I think they have a great team and developers. Their jobs are very fast and do not disappoint investors. even they are almost penetrating top100 coins in CMC, whereas MTC note bene is still very new in CMC. for now, I think MTC is still the best altcoin under 1 $