Ransomware hackers have escalated their extortion strategies by stealing files from victims before encrypting their data. These stolen files are then used as further leverage to force victims to pay. Many ransomware hackers have created data leak sites to publicly shame their victims and publish the files they stole. Here a list of sites in the dark web that list ransonwware leaks: https://github.com/joshhighet/ransomwatch/blob/main/docs/INDEX.md