So Who's Left? Characters That Have Yet to Appear in Tapped Out...

I think the most likely characters to be added in the near future are:

Level:
Helen Lovejoy
Jessica Lovejoy

Level (Maybe 50):
Cookie Kwan
Lindsey Naegle
w/ Red Blazer Realty

This would be a great opportunity for a landmark level update with a large land expansion. Possibly an entire 2nd "West Side" map.

Misc:
Sarah Wiggum
Lunchlady Doris
Jacqueline Bouvier
* Krustofski (I think this will be contingent who dies in the season premier)


Next most likely to turn up soonish:

Level:
Benjamin
Doug
Gary
w/ Springfield University
Springfield A&M University Pig

Level:
Lance Murdock
Daredevil Bart Costume
w/Springfield Gorge
Truckasaurus

Level:
Radioactive Man
Fallout Boy Costume for Milhouse
Dr. Colossus

Misc:
Ruth Powers
Mrs. Muntz
Judge Constance Harm w/ Houseboat


Eventually:

Misc:
Jebediah Springfield
Larry Burns
Laddie
Llewellyn Sinclair
Wendell
Lewis
Hamm
Janey
Allison Taylor
Ms. Pommelhorst
Plopper/Spider Pig
Principal Dondelinger
Herb Powell

Level:
7 Duffs
w/ Duff Gardens addition to Krustyland


Wishful thinking but feasible:

Misc:
Gil
Sideshow Bob
Laura Powers

Level:
Maggie
Baby Gerald

Any Phil Hartman characters:
Troy McClure
Lionel Hutz
Lyle Lanley

Matt Groening has REPEATEDLY said they retired all of those characters out of respect so I think it's very unlikely we'll ever see them because of that alone. But you never know...