In 2016 approximately 14GB of user data was leaked out of the polish telecom "Netia" by the group "Pravyy Sector" or "P.A.S."
See:
Link1 Link2 Link3
At that time, the data was leaked publicly and was available for downloading by anyone. The filename was "anon-netiaplfulldump2" or "netiaplfulldump2".
However in 2021 that data is not easy to find anymore - at least I could not find it on any torrent nor P2P sites.
Q: Does anyone of you know of any forums or sites in clearnet or DW that archive such stuff ?
Up till now, I have been doing only Reverse Engineering and coding and I do not know where to start searching for such data dumps...or even what people to ask.