Since all the good suggestions are taken, I want to mention a couple of diversions:
fortune: prints something silly or thought-provoking. You can get extra fortune cookie files or add your own.
cowsay: prints an ascii-art cow (or other creature) with a speech-bubble filled with the text of your choice. You can pipe fortune into cowsay for extra fun.
$ fortune | cowsay
______________________________________
/ Publishing a volume of verse is like \
| dropping a rose petal down the Grand |
\ Canyon and waiting for the echo. /
--------------------------------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||These days, there's also:
https://github.com/erkin/ponysay
My latest find is to use a combination of weechat and wee-slack for most of my slack usage (it's note quite there when it comes to editing, or in-line reactions). But works well for the chat part:
https://github.com/wee-slack/wee-slack
As a former BitchX and sometime irssi user, weechat feel cozy. And it doesn't eat all your ram just for chat.