Here’s some Unix tools everybody should know about. They’re third-party and not especially well-known.
fish
fish - the friendly interactive shell
“Finally, a shell for the 90s” is a great tag line. For a long time we have sort of had to decide if we wanted a better programming experience or a better interactive experience with the shell. Fish has a very nice programming language, but the ooh-ahh factor is definitely the command line. Check it out.
pv
A utility that works like cat, except shows progress bars. This thing makes a huge improvement on the UI of your shell scripts. I highly recommend it.
parallel
parallel - xargs for multiple cores
It has a number of nice modes, but basically it does what it says on the tin: run a bunch of stuff concurrently. By default it will figure out how many cores you are and make your machine busy, but not create a bunch of contention. I use this in file conversion scripts now to good effect.
entr
This is a great little utility for tying behavior to filesystem changes.
cronic
cronic - a cure for cron’s email problem
Useful for making it so you only get mail from cron when something happens you should know about.