Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
Worklife Slackbot - Your personal meeting assistant, in Slack
TextMe - TextMe is a free calls and messaging application at both local and international levels.
Meetingbird - Powerful meeting scheduling and notes — right in your calendar
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.
RemoteStandups - Join others and organise remote standup meetings together