Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
Momentum - Agile goal and performance management
TextMe - TextMe is a free calls and messaging application at both local and international levels.
Letz - Chat bot that will make you enjoy productivity
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.
QuietKit - Guided meditation for beginners (for free)