MiTeC Task Manager Deluxe - MiTeC
iStat Menus - "An advanced Mac system monitor for your menubar."
Process Explorer - The top window always shows a list of the currently active processes, including the names of their owning accounts, whereas the information displayed in the bottom window depends on the mode that Process Explorer is in: if it is in handle mode you'l…
Stats - Simple macOS system monitor in your menu bar.
WinID - WinID is controls & windows identification utility that is both powerful and compact.
MenuBar Stats - Advanced Mac system monitor right from the menu bar