Linphone - Linphone is an internet phone or Voice Over IP phone (VoIP).
TeamViewer - TeamViewer lets you establish a connection to any PC or server within just a few seconds.
Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems
AnyDesk - AnyDesk is the world's most comfortable remote desktop application. Access all your programs, documents and files from anywhere, without having to entrust your data to a cloud service.
Sipdroid - Free and open-source SIP/VoIP Client
LogMeIn - LogMeIn gives you fast, easy remote access to your PC or Mac from your browser, desktop and mobile...