On the Democratic side, Patrick Murphy is a huge contender. People thought the guy was a perfect choice for Senate in 2016 on account of an impressive win in a strongly republican year in a decently republican district, but as a General Election candidate was just a massive flop.
Not me. I tried to warn he was a max Romney donor who owed his career to his family wealth, who switched parties only due to opportunism but no one wanted to listen. Instead they wanted Debbie Wasserman Schultz at the DNC instead of running for Senate.