Broadcom, as you've discovered. That's the one brand that I've always had trouble with; they go out of their way to be closed source: never publishing specs, never responding to developers. They're horrible to the point where I will not buy any product that uses Broadcom chips. Which used to be a PITA because they were also common.

Fingerprint readers, in general, also widely seem to be poorly supported.

One of my computers has a MediaTek wireless chip where WiFi isn't supported but Bluetooth does.

A lot of people have problems with NVidia cards; I've not had trouble with either AMD or Intel GPUs (although, I think all Intel GPUs are CPU integrated?).

Multifunction printers are still iffy, and even just plain printers can give grief; I've come to believe that this is simply because CUPS is ancient and due for a completely new, modern printing service. It's an awful piece of software to have to work with.

The lack of support seems very daunting at first.

I started thinking "Oh I wish I could transition to Linux, away from Windows, but what about the latest hardware or random gadget?"

The trick is to flip the question around, namely not "Does my current hardware work with Linux?" but rather "Am I sure my next hardware work well with Linux BEFORE I buy it?" then this remove 99% of headaches. It's typically 1 Web search away from either a lot of complaints or positive feedback... or not much, and then it's up to you to see if you are ready for an adventure. If there is not much but there is some standard interface, e.g. Bluetooth, and no need for a proprietary application, it's nearly sure the main features will work. If a proprietary application is needed, then safer to avoid.

So.... yes maybe surprisingly a LOT of hardware does work well with Linux!

What does not work for me, to give a random example, is the LED controller of my desktop case, which I bought several years ago while Windows was still my main OS. I didn't put a lot of effort into it, cf https://gitlab.com/CalcProgrammer1/OpenRGB/-/issues/1683 but the recent article posted on this instance, namely https://lemmy.ml/post/32389687 makes me want to give it another go at some point!

Fingerprint sensor on most laptops

From the olden days: winmodem

Not technically hardware itself but Nvidia + Intel hybrid graphics have never really worked for me

nvidia cards are always giving people grief, especially on Wayland. Technically supported but practically not recommended if you want an easy time

iPhones

Some MediaTek WiFi cards are not supported. I had to replace one in a laptop.

Probably not the kind of hardware you're thinking of but I have an old Roland synthesizer, an Edirol SD-90, that did not work on Linux. Now, I didn't expect it to given the hoops I had to jump through just to get it to work on modern windows. So Linux seemed out of the question already. But can be a big deal depending on what you use your computer for.

Internal HDMI capture cards are barely supported, there are some professional brands like blackmagic that have support but nearly all consumer grade capture cards are not supported at all, because the companies who make them don't care about Linux.

USB based capture cards often work because they use the same standard protocols as USB cameras.

Also my Ricoh SP211SU Laser printer is not supported, my workaround is using Windows via VirtualBox if I need to print anything.

Many cheap chinese web cameras from non know brands,really problematic to make work printers which older from 2015 for example canon ,Lexmark cause they use proprietary communication protocols and thus drivers for inux or exist in shitty state which would not work on modern system but worked on Ubuntu from 2012 or not driver not exist at all and so on other very specific type of devices

the new one😂

I am surprised to unable to find this type.

Honestly, Linux has better support for the old hw, even better than m$ win.

My two biggest issues have been HDR and simulation hardware.

It's been a good few years since I've tried it but every time I've tried HDR my saturation just gets cranked to 11 and it looks like those nature photos that are edited to hell and back. Not sure why, and I've heard other people got it working so idk. I think it's just the Nvidia drivers doing their thing and not working.

But controllers for flight and racing Sims are the biggest headache to get working. And then when you do get them working you'll have issues with games running well and detecting them (I think this is actually due to proton/lutris), issues with force feedback, issues with the various buttons and sliders that aren't the primary axis. And then, after you spend hours getting them to work, it'll just break again the next time you want to play. My sims and FPS games are the only reasons I still have a windows install.

Anybody ever get Winmodems to work or did they all give up on it?

Back in the day, it was hard enough getting dialup internet working on Linux (especially before you had internet in your pocket, so you had to print out HowTos or write down a bunch of notes before you tried to do it).

But it was downright impossible with a class of modems that was designed essentially as a softmodem, heavily reliant on closed-source firmware and drivers, making them practically impossible to work on Linux.

Racing wheels lacks Linux support. It's the biggest, actually only, reason why I'm dualbooting with Windows.

I've been trying to get my Thrustmaster TX to work on Linux Mint but no success so far. I'm still a little bit newbie with Linux so that might be the reason why my wheel doesn't work (yet).

About 10% of the hardware in my 2016 MacBook Pro. Twice I've tried to install Debian on that Satan spawn using various gists online, and each time I ended up deciding it wasn't worth the time

Every other piece of hardware I've tried in the past works without fail, that MacBook irks me.

Some useful stuff for some laptops - worth checking if you're buying one for linux:

https://wiki.archlinux.org/title/Laptop

https://wiki.archlinux.org/title/Category:Laptops

Also this - i guess this is the inverse question though:

https://linux-hardware.org/

On the peripheral end, ElGato. You can usually get their stuff to work but they provide little to no support, usually have issues to work out, and you'll always be relying on third party replacements for their software.

I got a stream deck plus with the xlr dock, since even though I quit content creation I like what it provides and have no reason to downgrade my mic, but the thing has been a headache and a half ever since I switched to cachyOS.

Not going to surprise anyone but Windows Mixed Reality VR headsets aren't great on Linux, at least with controllers

Although that is improving!