Since I did this with 2026, here is the 2028 Senate map. Not a great map, but in a good year some possible flips. But a lot of vulnerable seats that will need defending.
A lot of vulnerabilities in Arizona, Nevada, Pennsylvania, and Georgia. Mark Kelly, Warnock, Fetterman, and Cortez Masto will be facing reelection.
New Hampshire might be vulnerable. Hassan will be up.
As for flips, North Carolina and Wisconsin seem the best shots. Budd and Johnson will be up for reelection.
Ohio will have a special election to fill Vance's seat in 2026. Special election candidates typically don't get an incumbency advantage, so maybe Ohio would be a possible flip in 2028 with the right candidate.
Maybe Iowa? Grassley will almost certainly be retired or dead. He'll be 95 at that point.
Maybe Kentucky with Beshear? Rand Paul is up for reelection.