iStat Menus - "An advanced Mac system monitor for your menubar."
MenuBar Stats - Advanced Mac system monitor right from the menu bar
Stats - Simple macOS system monitor in your menu bar.
Rainmeter - Rainmeter is a desktop customization platform.
Rooster - Local sharing community where neighbors share free resources
Open Hardware Monitor - Monitors temperature sensors, fan speeds, voltages, load and clock speeds, with optional graph.