MenuBar Statistics - MenuBar Statistics is a lightweight app that sits quietly in your menu bar of macOS and displays computer information such as CPU, Disk, and Network, which is updated every 5 seconds.
Venmon - Compact size system resources monitoring utility and multi-ping tool for Windows
Taskbar Meters - Incredibly simple meters that live in the Windows 7 task bar.
Curler by Amixr.IO - Curler by Amixr.IO is a lightweight tool that lets you monitor your website uptime by checking your site once per 10 minutes and let you know if it’s working or not.
Mousotron - Mousotron is a mouse and keyboard activity monitor and keeps statistics of your mileage. It's like an odometer or tripometer for your mouse cursor.
Scout - Scout ♥ monoliths.