I like this but i can't decide if it's technically abuse or not. The paste command will happily parse - (meaning read from stdin) multiple times, so for transposing a list into a table:
Back in the crusty old days, FreeBSD used to take forever to install over the network, but would start an "emergency holographic shell" on pty4. The 'echo *' trick and various other shell built-ins were very useful for exploring the system before /bin and /usr/bin are populated.
I like the simplicity of this one but it's not very useful day to day:
As a replacement for "ls".