Prefer - Professionals you need, from people you know
Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems
Warmspace - Tech-powered conversations that transform relationships in work and life.
MicroSIP - MicroSIP is a free portable SIP softphone for Windows based on PJSIP stack.
Introwise - All-in-one scheduling and business management platform for coaches, tutors and consultants to run their business online.
Sipnetic - Sipnetic is a free VoIP softphone based on the SIP protocol.