TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
Mitel - Business Communications and Collaboration
Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
Burner - Disposable phone numbers -- now with MMS photo support
XO Hosted PBX - Hosted PBX is a scalable UC solution that uses cloud technology to integrate HD voice & data services, mobility, along with advanced calling
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies