Stats - Simple macOS system monitor in your menu bar.
MenuBar Stats - Advanced Mac system monitor right from the menu bar
iStat Menus - "An advanced Mac system monitor for your menubar."
taskbar-stats - Display live system stats on Windows’s taskbar
MenuMeters for El Capitan - MenuMeters for OS X El Capitan 10.11 (and later)
Barsoom - Rearrange your menu bar items in any order you want, and keep your menu bar order between restarts.