I don't see anyone mentions htop. So, I will:)
Just works, could be installed in any distro. Much more friendly than top but isn't bloated with features as some other alternatives are.
On the subject of editors, joe is just awesome: lightweight, powerful, had coffee coloring and line numbers, and you can choose it with Ctrl+C:)
If you'd map it to just f it's even more handy
A really simple one but surprisingly useful is cal
Aggregating Matrix, xmpp, irc, and telegram could work for me. But I'd rather did this on my private matrix instance now though.
Terminator isn't supported anymore as far as I remember. A good substitution for it is Tilix. I'd been using the latter for a while but recently I switched to the new default terminal in Fedora (it had weird name that I unable to remember) and Tilling Shell extension for Gnome.
Fedora changed it to the one I'll never remember the name of;)
Personally, I'm looking forward for our to stabilize to try working on Matrix protocol support.
I was using this kind of a setup a long time ago with 120GB SSD and 1TB HDD. I've found the overall speedup pretty remarkable. It felt like a 1TB SSD most of the time. So, having a cache drive of around 10% of the main drive seems like a good size to cost compromise. Having a cache 50% size of the basic storage feels like a waste to me.
Fish for shell everywhere
Looks like it's time for Three Laws of Robotics to be deployed...