iStat Menus - "An advanced Mac system monitor for your menubar."
htop - htop - an interactive process viewer for Unix. This is htop, an interactive process viewer for Unix systems. It is a text-mode application (for console or X terminals) and requires ncurses. Latest release: htop 2.
Stats - Simple macOS system monitor in your menu bar.
smcFanControl - [Download] smcFanControl 2.
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…
OS Track - Keeps track of system resources.