StatusOk (Open source) - Get notified through Slack/email when your website is down
Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
UXPin + Slack - Keep tabs on design projects in Slack
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.