There are two precedents for impeachment after leaving office. The second was Trmp.
When Dems take over Congress, they need to bring impeachment proceedings against every official in this maladministration who arguably broke the law. The Constitution explicitly cites bribery as just cause, so that's several of them right there. Impeachment and conviction bars that individual from holding other appointed office later, and I would suspect kills any hope of a Federal pension, but I don't know that for a fact. So don't forget them just because they were fired by the Terrible Toddler in the WH, or chose to resign. Burn sulfur and smudge pots in their former offices and burn every bridge they could possibly use to return to practicing corruption in office. Don't give them a second chance to sabotage our Democracy the way the Iran-Contra conspirators and other Reagan-Bush trolls (remember Dick Cheney ?) were.
The nature of the impeachment proceedings is remedial rather than punitive, with the only remedy being removal from office. Since all officers in the federal government are confirmed in the Senate, officers appointed under the Appointments Clause of the Constitution may also be disqualified from holding any other appointed office under the United States in the future. As the process is not punitive, an individual may also be subject to criminal or civil trial, prosecution, and conviction under the law after removal from office. Additionally, the president is constitutionally barred from pardoning an impeached and convicted person to protect them from the consequences of a conviction in an impeachment trial, as the conviction itself is not a punishment.
https://en.wikipedia.org/wiki/Federal_impeachment_in_the_United_States