Kiwi application monitor - Kiwi application monitor is a small program which lets you monitor your applications/processes, Windows and User activity.
iStat Menus - "An advanced Mac system monitor for your menubar."
KillSwitch - KillSwitch is an advanced system monitoring tool that is apart of
Stats - Simple macOS system monitor in your menu bar.
Battle Encoder Shirase - Software that controls per-process CPU usage: an “active” software CPU cooler.
MenuBar Stats - Advanced Mac system monitor right from the menu bar