The above table from DailyKos does not include uncontested seats. I've long believed the biggest underperformances occur when one does not try at all.
Texas' 32nd district?
Whoops. I should have said it does not include overperformances and underperformances among districts that went for the same party for president (which is true). But Timmy's request appears to not have included those.
But, then again, I still think it was monumentally stupid for the Dems not to have run candidates in Buddy Carter's and Adam Kinzinger's districts.