UptimeRobot - Free Website Uptime Monitoring
Microsoft BitLocker - BitLocker is a full disk encryption feature included with Windows Vista and later.
Uptime Kuma - A fancy self-hosted monitoring tool.
Paubox - Paubox provides HIPAA compliant email encryption without the hassle of extra steps.
OnlineOrNot - Uptime monitoring for software teams (even teams of one).
OpenSSH - OpenSSH is a free version of the SSH connectivity tools that technical users rely on.