Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems
Topia - Create amazing wallpapers for your iPhone
Sipdroid - Free and open-source SIP/VoIP Client
Reminder - A better way to keep track of your reminders 📝
Linphone - Linphone is an internet phone or Voice Over IP phone (VoIP).
Geneva - An all-in-one communication app for groups & communities