Fax.to - Send a fax from iPhone or iPad with built in scanner
FaxSalad - Pay-as-you-go, secure faxing.
Fax Engine - Replace your traditional fax machine with your mobile number
Bitcoin Fax - Bitcoin Fax allows you to send a fax with minimal fuss. No sign up required. How it works:
iFax - IFax is one of the most popular software apps in its category. The app allows you to send a fax directly from your PC, tablet or phone. The software is available for the Windows, Mac, iPhone and iPad platforms... read more.
FAXY - Pay-as-you-go virtual fax