Twilio - Brings voice and messaging to your web and mobile applications.
Lurchr - Saves all your Slack links, so you can focus on work
Plivo - Plivo simplifies your customer engagement.
Slack News Feed - Get the top posts from every Slack chat you're in.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Slack It - A bookmarklet to share links in Slack with one click