It's sad when the next most relevant character is Helen Lovejoy

In fairness, Herman is a pretty retired character - when was he last in The Simpsons?

I'd quite like Troy McClure and Lionel Hutz. Especially if Troy has a 'Sleeping with fishes' and 'Planet of the Apes Musical Number' Task.

Also, Crandall and Gabbo (Gabbo! Gabbo!) could be a fun addition.

Captain Lance Murdock (With Springfield Gorge)
Mindy Simmons
Dewey Largo
Fallout Boy and Radioactive Man
Lurleen Lumpkin
Roger Mayers Jr (With Itchy and Krusty Studios) and a Marge tries to take down TV storyline

Yes some of these are one shot characters, but so what? Like Rex Banner you know they will never be needed in storylines so they can constantly do 24 hour (or longer) long jobs and help build up money

Also
Jaques
"Michael Jackson"
Mr Bergstrom