Mitel - Business Communications and Collaboration
TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
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
Burner - Disposable phone numbers -- now with MMS photo support
VoIP.ms - VoIP.ms is a VoIP origination and termination tool.