Comment by DominikPeters

I think pgfplots should in principle be possible. I've postponed it thus far because pgfplots is GPL licensed, while the editor is MIT licensed, so I would need to distribute pgfplots support as a separate add-on. But in due course, putting in add-on infrastructure could make sense, because it would also allow adding support for stuff like tikzcd and CircuiTikZ (or tikzpingus!).