Atop - An advanced interactive monitor for Linux-systems to view the load on system-level and...
Open Hardware Monitor - Monitors temperature sensors, fan speeds, voltages, load and clock speeds, with optional graph.
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.
Guru3D - Guru of 3D: PC Hardware Reviews and tests
Stacer - Ubuntu system optimizer
Geforce Experience - GeForce Experience is a new application from NVIDIA that optimizes your PC in two key ways.