StatusOk (Open source) - Get notified through Slack/email when your website is down
Troops Slack Sales Gong - The most customizable Salesforce Gong in Slack
Attentive - A marketing channel, built for retail & e‑commerce
Owlead - Grow your Twitter with valuable followers, effortless
Haark - Tracks your sites and notifies you if they're down
Do for Slack - Meeting summaries from Do.com straight to any Slack channel