I was under the impression that PIVX is also in this category.

It's main motto is:

Private - Instant - Verified - Transactions

It also seems hugely undervalued at present. Good team and sexy website!

I'd be keeping an eye out for this currency in the next few months-year.

Besides BTC, PIVX is one of my longest holds. I found it early and jumped on it. I think it'll do well in the future.