My understanding is that the range of crimes are associated with many of the usual rico/organized crime ring stuff such as money laundering, extortion, bribery, tax evasion, murder for hire, and then the range of human trafficking issues involving underage prostitution, possession, purchasing, production and distribution of child porn, and then there's all the drug stuff, and finally the really vile stuff. Plus treason and sedition at the highest levels.
Many of the arrests I suspect will have something to do with the fact that for at least 8 years, the justice department and FBI haven't been doing their jobs because of the shit for brains liberal leadership not wanting to enforce laws, or catch criminals. They've been playing catch up.