You could try the old program SpeedFan.
It's no longer maintained, but if you're lucky, it will control your fans, but don't count on it.
As I wrote, no longer maintained and I guess thanks to diversity and people being lazy buying ready-made solutions (not to mention water cooling, better chassis etc), and a general lost interest in tweaking stuff, I can't say I blame the guy who wrote the program, that he decided to pull the plug.
Just look at how many people are using Apple products (and they don't exactly boast with monitoring indicators and so on), and folks generally just want stuff that works (and happily goes to a repair-shop or buy new ones).
Otherwise, if you can't find a solution software-wise, you can always build a simple fan controller with just a few components:
Very simple, but effective. About 5 bucks maybe worth of components.
You can also build one with an NE555, a thermistor (NTC), a couple of small capacitors, a trim potentiometer and a transistor that can handle huge loads (I.e. many fans).
Cheap to make, it'll cost you maybe about 10 bucks.
I was unable to find the schematics, but if you're interested I can whip something up.
Not difficult to make.
Or, try to find something on Ali Express. There are several different solutions. One would be a fan controller that sits in the 5 1/4" bay and has a thermal sensor with a display, but that's just a glorified simple solution. Usually they're cheap. Don't have any, nor do I intend to as I prefer to build my own. I actually use one (With NE555) in my server to control 8 fans (4 at the bottom, 4 at the top) and it gives a pretty good airflow, but then I have a custom case too.
Just found this software which also is open source:
Currently not tested this one myself just yet.
I need to reboot first, and that might take days until then. It requires .NET 4.8 to be installed (You'll get prompted with the option to download this off Microsoft's webpage), and like many of their updates it requires a reboot to work.
Based on the image, it provides a bunch of options for monitoring and controlling, and I can't wait to try it out with my hardware. I've got 10 fan connectors - not all used - and the GPU as well.
I used to run SpeedFan, but I discovered that it conflicts with something which causes it to BSOD on me, so I'm about to try this to see if it works better.
Hopefully it won't since it's a bit more up to date (SpeedFan is very old and outdated, and not open source and hasn't been updated for years!).
I found it on this page:
Some are proprietary hardware specific software.
Perhaps something there will be of use.
Edit 2: I've tried out FanControl a bit, and there's support for a few devices.
Some additional sensors can be found by using a third party software, HWInfo32/64 together with a plugin (download link available from FanControl Git-hub page).
This plugin takes a thorough read for the instructions.
Basically, download it, copy to the plugin-folder for FanControl.
Open HWInfo, on the sensor status window, click "Configure sensors" (second from right bottom, cog wheel button).
Go to the tab "HWINFOR Gadget".
Click on "Enable reporting to Gadget"
Select the sensors you want, then check "Report value in Gadget" or else they won't show up.
After any changes are made, go to FanControl and click the horizontal dots menu (Right top corner).
Select "Refresh sensors detection".
You should be able to find them afterwards.
I also should point out that some sensors and controllers might now show in spite of them being selected, as your motherboard might not have support for externally controlled fans and other outputs.
The user interface takes some getting used to, as to find find what you're looking for. Somewhat of an acquired taste I'd say.
But, in my case I was only able to control my GPU fan (Which is why I was looking for an alternative to SpeedFan in the first place), and I can set it to follow a curve or a diagram. That's a very nice feature. SpeedFan is about as good and has a very similar function.
I will try this on my other machines and see if they can find the other fan controller chips as they vary much from different manufacturers.
This computer is the only one that has ever blue-screened on the account of SpeedFan.
So far, I've been able to run it for about 3 days now with no errors or reboots.