I don’t think DMCA stuff will be very relevant for most Fediverse servers (though being careful about federating with piracy focused communities may be wise), but this one stands out:

Service providers are required to report any CSAM on their servers to the CyberTipline operated by the National Center for Missing and Exploited Children (NCMEC), a private, nonprofit organization established by the U.S. Congress, and can be criminally prosecuted for knowingly facilitating its distribution. NCMEC shares those reports with law enforcement. However, you are not required to affirmatively monitor your instance for CSAM.

While I don’t think the NCMEC would appreciate being flooded with thousands of reports from federating servers all reporting the same content uploaded from one specific server once the next CSAM troll appears, this does pose more significant risks. The people who left their Fediverse servers running after kind of dropping out of the Fediverse (the many servers that were used to generate the spam waves we recently saw, for example) can easily accumulate a significant portion of illegal material to the point law enforcement actually starts caring.