Zesplot has undergone quite some development as part of our IMC submission titled Clusters in the Expanse: Understanding and Unbiasing IPv6 Hitlists (camera ready on arXiv).
Also, check out the Hitlist website that goes with the paper. Besides the updated hitlist, it also has interactive versions of the zesplots in the paper.
I'm refactoring the code, aiming at improved usability and error messages. Also I'm very eager to add more features. Follow the developments in the new GitHub repo.