I wrote a Common Lisp plotting library called cl-2d in 2009, and I have been using it for my own graphs ever since. I am currently working on a library that implements the same functionality but with a much more friently interface and a different engine, using LaTeX and pgf to generate the plots instead of cairo. This gives me a lot of useful features out of the box, including very nicely formatted formulas if I want to use them in annotations, and it is reasonably fast for my purposes.
I plan to remove the existing cl-2d repository from Github, put up a new one (it is a complete rewrite from scratch, there isn't much sense in carrying around the old source), and recycle the name (for both the package and the library).
I don't think that there is anyone out there using the current version of this library, but in case you are, please let me know soon.