D’oh! I just remembered: George Bush has appeared more than once as a character (and not voiced by the real George Bush), as has Bill Clinton. I think Bob Dole only appeared the one time, though…
Are Kirk and Luann Milhouse’s parents? I think so.
Jay Sherman (The Critic, voiced by Jon Lovitz) appeared twice.
Jacque has appeared in more than just a background scene (depending on your definition). He was on the bowling team with Princess Cashmere. I think they were the homewreckers.
Some of these might be repeats cause I don’t know their actual names.
Drederic Tatum
Homer’s brother(Danny Devito)Pimply-faced kid
Fat Tony’s gang
Jebidiah Springfield
One armed guy
Burns mother and father (possibly a stretch but I think they showed characters identified as Burns parents in two episodes but continuity problems makes it hard for them to be the same people )
Rich texan business man
Dolph
Herman
Capital City Goofball (has appeared in the background sometimes)
Shotgun Pete (officiated H&M’s wedding)
Luigi (w/Chef Boyardee hat)
Ruth Powers (neighbor)
Don Vittorio (Mafioso)
Lucius Sweet (boxing promoter)
Birch Barlow (Republican)
Billy (appears in educational films w/Troy McClure)
The Happy Little Elves
Woody Allen, Barbara Bush, and Fidel Castro have appeared as a character but were never impersonated by the real person
God
There’s also the three nerds (“My computer has 512 shades of red!”) Homer went to college with that appear in at least two episodes. I can’t recall their names.
Also, Bart’s Sunday School teacher was in a few episodes. I don’t think she had a name.
Lurlene Lumpkin (I think that was her name), the country singer, appeared twice. The first one where she was discovered and managed by “Colonel Homer”, and then a later one where she appeared (IIRC) at an awards show, ruined voice and fresh out of the Betty Ford clinic.
She’s been in the background a couple of times at the Elementary School.
Hey, we’ve forgotten Diamond Joe Quimby.
Who’s the “other” female teacher (not Ms. Crabapple), the one with glasses that I usually refer to as “Lisa’s teacher”?
Mrs. Hoover
New Additions:
Leopold (“Allright, listen up you little frrrreaks. . .”)
and
Akira (as a Karate instructor, a waiter and explainer of Mr. Sparkle).
Lisa’s nerd friends, Data and Email.
Is it not Handsome Pete?
I don’t know if this counts But Frank “Grimey” Grimes was mentioned in one episode and his neglected grave was shown in another.
Oh yeah I just remember it he was mentioned when homer found a program for Grime’s funeral with a photo of Frank.
“I wonder what happened to him?”
Poochie also made a second appearence.
Aye Aye Aye, the Bumble-Bee Guy
Baby Gerard with the unibrown.
Herb Powell is Homer’s half-brother.
“Well, I never.” The snobby lady.
Did John the gay guy and Cecil Terwilliger ever appear again?
God showed up once. He was on his way for a tortilla appearance in Mexico.
Another one occurred to me: Johnny Tightlips, the gangster. He’s had speaking roles in at least two episodes.