CPU Frequency Selector - Cinnamon CPU Frequency Selector Applet
CrystalMark - CrystalMark is a full included benchmark application that can be utilized for surveying the execution and capacities of a PC.
Udev Discover - A helping tool for udev testers, coders, hackers and consumers.
3DMark - 3DMark includes everything you need to benchmark your hardware in one app.
CPU-Z - CPU-Z is a freeware that gathers information on some of the main devices of your system : Processor name and number, codename, process, package, cache levels.
Geekbench - Geekbench 4 measures your hardware's power and tells you whether your computer is ready to roar. How strong is your mobile or desktop system?