I will simply list a couple of the images^[1]^ I've used over time and provide some personal insights (in alphabetical order):

• Alpine; when I'm restricted in bandwidth and/or disk space. FWIW, apk is even faster than whatever is found on Arch.
• Arch; if I just need a certain package and can't be bothered to look up if it's available on any of the others. Yup, the AUR strikes yet again. Furthermore, if I'm troubleshooting and I find myself on the ArchWiki, then in order to prevent edge cases from happening and thus the provided solutions to not work on the non-Arch distrobox; I rely on the Arch distrobox. It doesn't hurt that pacman (or any of the AUR helpers) are blazing fast. However, if I intend to rely on said AUR packages over longer periods of time, then I often do look for an alternative distrobox to grab the package from instead. While the AUR is excellent for the amount of packages it has, the security standards aren't the best. Thus, if you're security-conscious, then it's better to rely on AUR packages sparingly, unless you're willing to get into the nitty gritty and check how they're built, how the package is maintained and if its maintainer(s) is reliable.
• Bazzite-Arch; my go-to for gaming.
• Fedora; as I'm already on Fedora Atomic, relying on Fedora distroboxes makes the most sense security-wise. Fedora is also known to take security very seriously themselves, so in general this is just very pleasant to rely on for security reasons. The only reason why one should not rely on Fedora for security reasons would be if they're already on something from openSUSE (like Aeon/Kalpa/Tumbleweed etc). In that case, going for an openSUSE distrobox makes more sense for security. Furthermore, if the package I need is one that's widely accessible, then I also rely on Fedora distroboxes. Lastly, currently, my development environments are all Fedora distroboxes. I might eventually change these to Wolfi distroboxes or simply rely on Nix, but that's still WIP for me.
• Ubuntu; I've had to rely on these a couple of times to use software that's known to target Ubuntu. Most recently it was with Matlab IIRC.
• Wolfi; For the security-conscious, this is probably the best choice. Unfortunately, I've only experimented with it so far without too much success. Thankfully, the Bluefin project has made some good use out of it. So I'll try to emulate their ways in the near future.

Notable mention goes out to Davincibox. Unfortunately my laptop doesn't have a dedicated GPU, so I can't make use of it. But it's something I'm keeping my eyes on.

NixOS is not a supported container distro, but I do have Nix installed through The Determinate Nix Installer. It's somewhat underutilized currently, though 😅.

1. The images will be the toolbox ones if available.

You can use multiple distrobox images. Pacman has a huge advantage of AUR.

I use Fedora Atomic with Distrobox.

I asked the same question a while ago and decided to settle on Arch as container.

Why?

• Pacman is extremely fast. I used a Fedora-container a while too and it was extremely slow compared to Arch
• Simple syntax, especially with the Arch plugin for zsh.
• Minimalist
• Official packages are (almost) just as secure as from other distros
• I get the newest stuff
• Good documentation
• The AUR. I rarely need to use it (pretty much never), but if I would need to, it's great I can.

I still rarely use it. I'm leaning more to the casual user side and use Flatpak 99% of the time. But for terminal use, I find the said container, with zsh + plugins great. There are some programs (Nextcloud client for example) that don't work 100% with Flatpaks, and for that, the Arch packages are actually pretty reliable and work almost every time (via distrobox-export).

I had a few doubts about Arch, and I personally still wouldn't use it as distro for everyday use, but at least as container, it's elegant and lovely. I could use Silverblue as unbreakable base and install everything with Arch, and nothing breaks.