join-lemmy.org regularly crawls all active Lemmy instances to keep the instance list updated. Additionally it also collects data from all Lemmy communities. The data is now publicly available in the following git repository:

https://github.com/LemmyNet/lemmy-statistics

Check the readme for details about the available data. Interestingly the numbers are quite different from other websites:

Here are some ideas what to do with the data:

• Recreate the Lemmymap, graphically showing the connections or defederations between instances.
• Render graphs, which could be added directly to join-lemmy.org (#532).
• Investigate what is causing the different numbers shown above.
• Run various types of analysis, like this one done by @malsadev.
• Build a tool to help users discover interesting and relevant communities.