FluffyChat - Open. Nonprofit. Cute ?
TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Dingtone - Dingtone is a free call and texting application for making unlimited calls and text messages to any number at the moment registered in any part of the world by any cellular company.
Molly (Signal fork) - Molly is an independent Signal fork for Android
Talkatone - Android App on. Google Play. Stop paying for cell minutes, texts & landlines; Turn your iPad or iPod touch into a phone; Call/Text even in areas with bad cell coverage; Call/Text when travelling without paying for expensive international minutes.