There’s a Reddit thread on diagramming tools that work with #orgmode. I noticed that #ditaa is a drawing tool that still works, so I contributed to the thread:
https://www.reddit.com/r/emacs/comments/13d38zq/comment/jjn96u6/
Quoting myself:
ditaa still works within org-mode. The nice thing is that artist-mode kind of produces ditaa compatible ASCII drawings.
The (outdated) documentation states that the ditaa jar comes with Emacs, but that’s no longer the case. So download it and then setq org-ditaa-jar-path /path/to/ditaa.jar in your config.
https://orgmode.org/worg//org-contrib/babel/languages/ob-doc-ditaa.html