I work for IPinfo — I described my process of how I made the game in the other comment.

Using a dataset-based implementation would require me to have a backend, which is out of the scope of this project. Right now, I'm generating random IPv4 addresses, but if I were generating random IPv6 addresses, I would have to go the database route. For that, I would use our free IPinfo Lite dataset: https://ipinfo.io/lite

My colleagues actually developed an extremely fast algorithm to select truly random IPv6 IPs from a series of CIDRs, which is what you see reflected in our dataset.

Let me know if you have any feedback or suggestions for me, please.