FBI Search and Seizure at Trump's Mar-A-Lago Residence, August 8, 2022, Case Dismissed July 15, 2024

Well, if a suspect, generally none- that is what the 5th is about. A Grand Jury, etc can order someone to testify if they are given immunity.

If a witness, they can be compelled to testify via subpoena, etc.

Civil matters, which these lawsuits- are have different rules.