Around the time I implemented the neat little waiting animation in SBWG I stumbled over a bash script that displays such animations. It actually gave me the idea. I mean, it's not a useful feature at all in SBWG. I just did it because I liked how fancy text based waiting animations can look with modern unicode fonts. I didn't use the code from the bash script that I found, or one of the animations (although there is a similar one there). So it effectively has nothing to do with SBWG and I don't know why I had to mention it here again. Anyways.
Here is the script on GitHub by Silejonu. There are some very nice and really creative single-line example animations in there.