The Open Hardware Monitor is a free open source software that monitors temperature sensors, fan speeds, voltages, load and clock speeds of a computer.
There has not been any code change since December 2020, also the community now wonders if it is abandoned: https://github.com/openhardwaremonitor/openhardwaremonitor/issues/1471 There also seems to be a fork called LibreHardwareMonitor (which is already listed as an alternative) and appears to be the most active fork right now.
SpeedFan is a program that monitors voltages, fan speeds and temperatures in computers with hardware monitor chips. SpeedFan can even access S.M.A.R.T. info and show hard disk temperatures. SpeedFan supports SCSI disks too.Discontinued
The developer promised new versions, but the program seems to be no longer updated. Latest version, 4.52, released in June 2016, can be still downloaded from the official website.
Core Temp is a compact, no fuss, small footprint, yet powerful program to monitor processor temperature and other vital information.Bundleware
The installation may contain adwares. Be careful during the installation: https://alternativeto.net/discussions/applications/11718/be-careful-in-the-installation/
Fan Control is a focused and highly customizable fan controlling software for Windows. It supports multiple temperature sources in min, max and average configurations, and fan curve functions, including but not limited to, linear, graph, and mix to control a single fan.
WinBar is a free and compact program that lets you monitor your system and provides easy access to frequently used controls. WinBar will run on Windows 2000 and newer operating systems and is available in 32 and 64 bit flavors.Discontinued
The project is no longer developed. Last version, 2.0.1, released in September 2009, can be still downloaded from SourceForge
Command line program that allows control of fans in Apple computers in Windows. Planned features: Automatic temperature control, temperature monitoring, rule creation for fan control based on temperature thresholds. No longer in development.
Speed fan controller and temp monitoring for MacBook Pro Unibody (Nvidia) for Windows under BootCamp. It allows to control MacBook fans speeds depending on the CPU and GPU temperature.
SysMetrix is a skinnable clock and metering application. Its purpose is to provide system metrics in a variety of interesting, useful, and cool ways. It can monitor and report on the hundreds of statistics
No recent release activity and download on site leads to 404 page.