According to the House of Representatives webpage, Duncan D Hunter of California's 50th district is still a Member. That means he will be eligible to vote on the impeachment bill, even though he has announced that he will be retiring after the new year turns (I suspect that the delayed resignation is a ploy to earn another year on his Congressional pension).
He really has nothing to lose politically, unless he thinks there is a place for him in California Republican politics despite his ruined reputation. He has taken at least twice an oath to defend the Constitution, so this would be a good time to admit reality and vote the impeachment bill.