There are tons of computers running Linux besides PCs. By far the biggest part are servers and supercomputers. Microsoft even has their own distribution for their server business. Then there are all the Android phones and devices. Android is Linux. In Germany I've also often seen Linux used for kiosks at government agencies.

Linux is used in TVs and set top boxes. Everything that says Tizen or WebOS is powered by Linux. I've also seen it used as in-flight entertainment systems. And Lunduke had an example of Linux running on a machine controlling how cows are milked, if I recall correctly.

For most systems you won't actually know what OS is used until you see a hardware error screen. Although Microsoft has made it a little easier with mandatory updates.

The Deutsche Bahn uses Linux for the displays in their trains, that show you the next stops, at least. Saw the systemd startup thingy on one of those displays once when the train restarted while I was in it.

my old GPS device runs on Linux. My PC also runs on Linux. To transfer updated maps from the PC to the GPS you needed a proprietary software that only ran on Windows. God, that pissed me off.

I saw the self checkout machines in my supermarket being restarted a few times and caught a glimpse of what was shown on the screen. Before they were upgrade some time ago they showed that CentOS was running and now I think that I saw Rocky Linux running on there. So yes, these are definitely out there and used widely.

Also I've see pictures of Raspberry Pis being used almost everywhere.

I want you to imagine an electronic device. Congratulations, you've imagined a device that runs some form of Linux...

Linux is much more commonly used in embedded systems than Windows for obvious reasons.

Yes. My work uses Ubuntu for certain touchscreen PoS devices they sell to their customers. It runs their proprietary apps automatically, and the end user doesn't know or care that it's Linux underneath.

A ton of digital signage (think fast food restaurant menus) run Linux as well.

Most home routers do as well.

My company has a robot scrubber that runs a custom Linux distribution.

The digital sign the local university has is powered by a Raspberry Pi - I caught it rebooting while driving past

Linux on phones and tablets is a thing. Typing from my Xiaomi Pad 5 Pro running postmarketOS and LibreWolf.

Not sure if that's the kind of device you are asking about but kobo e-readers run Linux. It's allowed me to sideload my books over SFTP instead of always having to plug in a USB cable

I have had seen a few in-flight entertainment systems crash and reveal that they run Linux. The crashes have been due to network issues as far as I could tell ( so no strike against Linux for that ).

Similar story for display panels at fast food places and hotels. Online, I have seen at least one Linux billboard.

My company uses Linux extensively for video monitoring systems in vehicles like busses, fire trucks, ambulances, and police cars.

Examples I've seen in the wild:

• Argos POS terminals using CentOS
• ATM using OS/2 Warp
• Co-op tills running (I think) Windows Embedded POSReady
• TVs using Yodeck (ultimately Raspbian, I guess)
• Occasionally, ad terminal things using Raspbian

Pretty sure ATM runs on super old stuff like OS/2 or Windows XP or Windows CE ?

I've got two Orange pi zero 3's (one acting as my "home lab" and the other one as my... lab rat.) which aren't ATM machines or PDA's, but... they are more like "very confused potatoes who think they are pcs" and everything "just werks" as intended.

There's a jack-in-the-box here that runs linux on their drive-through screen. I only know because it's had a "vmlinuz not found" error for a few weeks now xD

Most digital signage I see is a Chromebox running a specific kiosk software.

android on occasion as well

Some automotive infotainment systems run on Linux.

I came across a bowling arcade game that ran Linux. Still kind of wishing I'd bought it.

Pretty sure it's this one.

There’s not a distro because the companies that sell those pieces of equipment have their own software packages that sit on top of some distribution that they sell as a whole doohicky they call an appliance.

The distributions that are most often used are those with either direct support from a company the appliance manufacturer can work with or some distro that’s feature compatible with one of those kinds.

A local shop has these self-checkout registers on which I saw they're running CentOS.

I saw Linux used on Boeing passenger service systems.

I recently saw Domino's Pizza uses this touch device to take customer order that uses some very old version of Ubuntu (with unity DE)

I worked in retail until 2016, and a few years before I left they switched all the PoS registers to Linux.