The data this is based on comes from https://lemmyverse.net where you can just download a full json of the data they have (I excluded all communities marked as "suspicious")
EDIT: The data if you sort by active users last month:
I used recharts
Though one rendered it with google charts and that did look a lot nicer, but if one fine tunes it, then it will probably look equally good
If you're willing to post your code somewhere or send it to me somehow, I might have to find some time to integrate it on lemmyverse - also welcome to submit a PR if you have the inclination https://github.com/tgxn/lemmy-explorer