I still use the mutt email client when I'm remoted into some of my FreeBSD servers. It might not be the most eye pleasing email client ever, but it's powerful, lightweight and fast.
What do you do if you don't have dos2unix, need to convert a file or three from DOS (or Mac) format to UNIX format, but all you have is Emacs? Well, of course you use Emacs for the file conversion, what else?
I used XEmacs quite a lot in the 2000s before I switched back to the more stable GNU Emacs. That was back then before GNU Emacs offered a stable official Windows build when XEmacs did, and at the time I was doing a lot of Windows development.
I've been an unashamed fan of the old "cheese grater" Mac Pro due to its sturdiness and expandability. Yes, they're not the most elegant bit of kit out there but they are well built. And most importantly for me, they are expandable by plugging things inside the case, not by creating a Gordian Knot of hubs, Thunderbolt cables, USB cables and stacks of external disks all evenly scattered around a trash can. Oh, and they're designed to go under a desk. Where mine happens to live, right next to my dual boot Linux/Windows development box.
I've been a Xubuntu user for years after switching from OpenSuse. I liked its simplicity and the fact that it just worked out of the box, but I was getting more and more disappointed with Ubuntu packages being out of date, sorry, stable. Having to rebuild a bunch of packages on every install was getting a little old. Well, they did provide material for all those "build XXX on Ubuntu" posts. Recently I've been playing with Manjaro Linux in a VM as I had been looking for an Arch Linux based distribution that gave me the right balance between DIY and convenience. I ended up liking it so much that I did a proper bare metal install on my main desktop. The install was pretty smooth apart from a issue with getting my AMD RX 470 graphics card to work.