This stack overflow thread had a pretty good list of terminal plotting tools:

https://stackoverflow.com/questions/123378/command-line-unix...

gnuplot, feedgnuplot, eplot, asciichart, bashplotlib, ervy, ttyplot, youplot, visidata

And there's a lovely ASCII plot in the AWK book: https://dn790008.ca.archive.org/0/items/pdfy-MgN0H1joIoDVoIC...