That was a different girlfriend. Bea was the good one. 
My #2 is Lucy Lawless (not Xena, of course)
For my second character, I’ll go all the way back to Some Enchanted Evening, which was supposed to be the premiere episode.
Lucille Botzcowski, a.k.a. Ms. Botz, a.k.a. The Babysitter Bandit.
Kirk Van Houton
Milhouse
I mean the Milhouse from Shelbyville.
M1. ‘Is this the end of Milhouse?’
M2. ‘But Milhouse is my name!’
M1. ‘But I thought I was the only one!’
M2. ‘A pain I know all too well.’
M1. ‘So this is what it feels like… when doves cry.’
Can’t Believe we passed Binky up this far! I mean if anyone is truly Iconic of Springfield, its Binky.
Jub jub.
No Lenny or Carl? Or did I miss that.
If I did then I’ll add Dr Colossus
I did read the thread and I don’t recall this one being mentioned, so for my second contribution:
Cletus’s girlfriend/sister? Brandine.
“She been makin’ eyes at that photographer what come to document our squalor.” 
Can I add a second if I didn’t vote in the first 100?
Lurleen Lumpkin
I’m adding 3rds and 4ths because I want to see them and because, perhaps, the first hundred were ALL THE HUNDRED who could help out in the thread. I give you:
PINCHY!
The unofficial Symbol of Springfield.
No he isn’t. Binky is from “Life in Hell.” Blinky is the Sprignfield 3-eyed fish.
So… if SpongeBob was in heaven with Jesus & Buddha, wouldn’t that be 3 characters? Assuming we even want characters who appear briefly in one episode…
Well, the OP did say that one time appearances were acceptable. Though you could call Jesus a recurring character, I seem to recall him in several episodes. Or was it St Peter that Homer met when he died…hmm
St. Peter gave Homer the tour of Heaven, where he met God. Jesus appeared only as the robed man sitting silently on a swing, about whom God sayid “I sent my son down there once. I don’t know what you people did to him, but he hasn’t been the same since.”
I just saw Jesus last night…er, on the Simpsons, I mean. Appearing to the Flanderses as they inhale the exhaust fumes coming from Homer’s RV camp.
I see people are taking second turns, so I will as well: Stonecutter # 1 (he didn’t have a name, did he?)
Paul Lynde (at least, I assume that was supposed to be him, as the effeminate Boy Scout leader/supervillain in the first “Radioactive Man” movie).
I’m going to go ahead and post a 3rd. I hope this qualifies as a “character”…
[Nelson Muntz] HA-Ha! Post 93! [/Nelson Muntz]
Hank Hill