I have some old PCs that will not be able to handle Windows 11 so I was wondering if anyone had any recommendations?
This is a list of the ones I have found
Some Other Links
I use Linux Mint on all our home computers, both old and new. Flawless. Have everything we need
I would choose Fedora KDE:
I use ubuntu budgie, have done for the last decade. As you are learning on a ubuntu server it may be an idea to stick to some debain/ubuntu distros as the learning curve will be shorter
I think you are right for me to stick with Ubuntu, but I will look a that Fedora one for reference as it looks like windows. I think I have to look at a few of these.
Mint and Ubuntu use different packages/managers SNAP and not SNAP 
I know Fedora is one of the few Linux distributions that makes all of their own packages, i.e. no upstream distro.
I had Mint running on an old laptop and it was easy to use.
Using MX Linux as a dual boot and loving it
You didn’t precise what are you requirement.
I would add Parrot or maybe even Whonix (Hardcore security, Gateway, VM …. )
I know it’s obvious but it’s not in your list: DEBIAN 
If it’s for everyday You already mentioned Ubuntu or Zorin. I think they both fit.
There was also Garuda but It was based on Arch Linux so I never tried.
If you want an exhaustive list, you can check here:
A Window replacement for the machines that will not run windows 11 and will ease me into Linux.
I’m not a user of Linux on a PC (like yourself am pretty solid Windows (* from 3.1 through to 11*) on all sorts of hardware). but doesn’t the choice boil down to what hardware you are installing on? (ie. drivers, bios, etc)
Linux remains more backwards compatible than Windows. Microsoft has a financial stake in obsoleting stuff.
windows 11 has certain criteria such as a supported CPU
For Linux to be fully mainstream it needs a good GUI and not as many different distros.
Fedora Workstation continues to be my favorite desktop OS. It’s very up-to-date, maintained by more upstream developers than any other distro (last I heard, Red Hat employs more kernel, Gnome, GTK, systemd, etc. developers than anyone), and looks nice right out of the box. And, it works fine on older machines, generally speaking. If the system is really old/small, you might want the Xfce or LXDE or LXQt spin.
Linux already has the best GUI. Gnome is excellent. 
I hate when I have to work on Windows or a Mac.
Linux Mint for me. Installed in an old MacBook Pro from 2009 (works perfect), and in a HP elitebook.
If you have the time to explore try a few of them, install different desktops and see what works for you, I was running Mint on a very old Notebook but not powered it up recently. For my other desktops I always use a Red Hat-based distros, currently back on Fedora.
I think a GUI is a personal choice, I use Fedora on my desktops and Ubunto on my laptop, my GUI of choice on all is Mate. Before switching to Linux I used Windows and Mac, the Mac had a great GUI, very easy to use and the system was logical. My first Fedora (7) was using Gnome 2, hated it when they switched to Gnome 3.
I also hate it when I have to use Windoze I so rarely use it I can never find what I am looking for.
Linux Lite is decent for lower resource older stuff , Lubuntu does a fairly decent job as well. Never got around to trying it but some folks speak of Void and Mint seems to be fairly popular as well.
Well the OP has a great question. The use of Linux allows for older equipment to work much better. We get better performance, security and we don’t have to pay for a lousy OS.
Distrowatch.com is the place to go to search the database for what you need, based upon features you pick.
I started on a DEC computer with BASIC, used an Apple, and an IBM with DOS. Of course we moved to a GUI environment eventually, and then put up with the microsoft monopoly for way too long. I finally decided to follow my conscience and move to Linux.
I’ve tried many distros. The good folks here will point out that server is different than your home or office PC. That said, my personal usage has finally come down to Debian. It is stable and supported for a long period of time for each version, and that is a big plus. Also, it allows different windowing systems, window managers and many desktop environments from which to choose. The customization possibilities are awesome.
One of the things in computing is that people like the latest versions. Debian only supports the proven versions of software programs. Still, there are other ways to install later version if need be.
I do not recommend anything from Canonical such as Ubuntu or others of theirs. They do not have good tech support as they tend to be quite parochial and proprietary.
There are some basic decisions you have make before “choosing a linux”.
Are you going to “do DEB or RPM or ARCH” (meaning “Debian-based” or “Redhat-based” or “Arch-based”)
Are you going to “drink the UBUNTU koolaid” or not
Are you going to do “GNOME or KDE or CINNAMON or XFCE”
Are you going to “SNAP or NOT SNAP”
(my worthless opinion) I no longer do Redhat or Ubuntu or Snap or Gnome.
If you are willing to “do Ubuntu”:
YES → Linux Mint Cinnamon
MAYBE → Pop OS
MAYBE → Kubuntu
If you do NOT want Ubuntu:
YES → MX Linux (have to decide between XFCE or KDE)
If you want to “do RedHat”:
YES → Fedora (have to decide on GNOME or KDE)
If you want to “do Arch”:
YES → Manjaro
MAYBE → The Chris Titus Arch Installer
P.S. Though I don’t “do Gnome” I do agree that, at this time, it is the MOST supported DE on the planet.
I definitely have some homework to do, but I do appreciate all of the feedback.
A biggy is, to Ubuntu or not😃