MenuMeters for El Capitan - MenuMeters for OS X El Capitan 10.11 (and later)
Stats - Simple macOS system monitor in your menu bar.
iStat Menus - "An advanced Mac system monitor for your menubar."
eul - System & Hardware and OS & Utilities
Hardware Lister - lshw (Hardware Lister) is a small tool to provide detailed information on the hardware...
GKrellM - GKrellM is a single process stack of system monitors which supports applying themes to match its...