HUGE uter fan here and Groundskeeper Willie is a fun one. I love Cletus and his brood so anytime they are around is funny.
Seconded.
Or thirded…
Whichever…
I always thought that Groundskeeper Willie would be the great star of an adventure-themed spin-off. Kind of like Indiana Jones, travelling around the world, but doing things in a way only Willie can.
Anyhoo…
But Discus Stu was so much better
The young Burns was a fascinating creature - I’d love to find out how he developed. Just how did the teenage Burns spend his time? And his early years in the power industry?
You may find this hard to believe, but in his salad days, his crowning glory was a bright shock of strawberry blond curls!
I tend to favor the really minor Simpsons characters, i.e. one or fewer lines. Among my favorite are Paint Drinking Pete from the hunger strike episode, and Jose Flanders. Buenos ding-dong-diddly dios, indeed.
I’d like to see an episode with Jasper and his mighty paddle.
Oh yes. He’s my favorite character, next to comic book guy. Does he even appear any other times besides the special Springfield episode?
On the other hand, that cameo he did there was perfect, you can’t do much more with him. Maybe have him drive in the background in his stupid little Beetle on occasion.
I think I read around here some time ago that they tried to do an episode where Karl came back, but Harvey Fierstein ended up saying no because he thought the script was bda.
HERETIC. Under no circumstances could or would or should any Hartman character return. There was a show where Gil played an attorney, and all I could think was “What Lionel Hutz could do with that scene.” 
The fact that so many people mention Hank Scorpio shows that his 15 minutes of fame were really memorable.
I imagine that Michael Jackson is out of the question…
Or Mr Bergstrom.
I’d like to see more of the gang of nerds from Springfield Elementary. Didn’t they call themselves the “Superfriends”?
Yeah, but I can’t for the life of me remember who was in it beyond Lisa and Database (the kid with the glasses). Anyone know?
I’m surprised no-one’s mentioned Snake yet. His (usually throwaway) lines always make me laugh.
Other than Snake, count me in as another vote for Duffman. “Duffman is thrusting in the direction of the problem!”
Speaking of the Phil Hartman characters: One idea for a Simpsons episode I have thought would be cool would be based on the fact that 2 of the 3 ex-husbands of Selma are “retired from the show”. So have an episode that starts with Hutz and then McClure found murdered. Sideshow Bob starts to get really sweaty. The big shoe on the other foot and all.
Now, I know what many of you are thinking: “Wouldn’t a Simpsons involving murder and Hartman’s old characters be in bad taste?” Umm, what’s your point?
I went an looked it up, which is really what I should have done before I posted in the first place. There’s Ham, Email, Cosine, Report Card, Database and Lisa. All named after their interests. They call Bart Cosmos in honour of his comet.
Anyway, bring 'em back.
Hmmm, how about a Wigglepuppy episode?
Requesting a Jasper episode? That’s a paddlin’.
Stacey Lavelle, the embittered oft-divoirced alcoholic creator of the Malibu Stacey doll:
Lavelle: The company forced me out in 1974. They said my way of thinking wasn’t cost-effective.
Lisa: That’s terrible.
Lavelle: Well, that, and I was funneling profits to the Viet Cong.
I LOVE Scorpio. He was so funny! I think he is definately the best minor character ever.
However, I have a huge spot in my heart for Karl, the angel asisstant. He was the lovliest piece of animation I have ever seen. Ever. My eyes still cloud up when he kisses Homer, since his mother told him never to kiss a fool. And when he gives Homer his umbrella…
However these two characters I think need to reamain in their own episodes, unless they did something really clever with either of them, I just don’t think that they could really make a new story of either of them, or at least one that was decent.
I WOULD like to see however;
The Cat Lady
The “Sexual Predator” who keeps switching jobs. She worked for Zovuzazz (The Phone Company I think) when the Simpsons went to Bazil. Her name escapes me though.
Rex Banner
Gil
Guy Incognito
The Three Nerds Homer met when he went back to college
And the talking coyote from el mysterioso something spanish something
Lyndsey Nagel.
Well, this may be unlikely since the death of Johnny Cash.