Holly Website Audit - Free, brandable website audit for your potential clients
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Crowdcurity - Crowdsourced web security. Connecting businesses with security testers.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Virusdie - All-in-One cloud-based, simple, powerful and gorgeous website security tools built for everyone.
Better Uptime - We call you when your website goes down