This wasn't a tech fraud like Theranos or Ubeam though. Quintillion did build a working fiber network. The CEO faked numbers to their investors, but they had a real working product, and the company is still in business providing internet access.
I'm going to make a bet that the next one on the list will be infiBond. Israeli A.I. startup valued at something like 1.25B[1] but doesn't seem to have ever done anything.