Let's discuss working titles, titled for cartoons that were used by the staff during production that changes before it's completed or releases. This could either be due to plot changes, or better wordplay, or whatever. I'll go first.

Disney cartoons
Donald Duck in Nutziland >>> Der Fuehrer's Face

Mr. Duck Gets His Wings >>> The Flying Jalopy

Gull Crazy >>> The Simple Things

Looney Tunes
It Happened All Night >>> Porky's Badtime Story

Bugs Bunny and the Gremlin >> Falling Hare

A Hunting We Will Go-Go >>> Quacker Tracker

The Simpsons
The Anti-Immigration Song >>> Much Apu About Nothing

Lisa Goes to Camp >>> Homer's Phobia

The Kent State Massacre >>> You Kent Always Say What You Want

Family Guy
Anchorwoman: The Legend of Lois Griffin >>> FOX-y Lady

Road to '85 >>> Spies Reminiscent of Us

Crip Off the Old Block >>> Poppa Has a Rollin' Son

My Little Pony: Friendship is Magic
The Tortoise and the Mare >>> May the Best Pet Win!

Reading Rainbow >>> Read It and Weep

Bully for You >>> One Bad Apple
PopKorn Kat
A few working titles are displayed in the Walter Lantz Cartune Encyclopedia. A few of these are actually listed as separate titles in some version of Jeff Lenburg's The Encyclopedia of Animated Cartoons.

Foiled! -> Let's Eat
A New Deal -> Confidence
S.O.S. Icicle -> Hot and Cold
Be Prepared -> Recruiting Daze
What's Cookin' -> Pantry Panic
"The Procedure of Slap Happiness">>>"Beep Beep!"[road] [coyote]

(This was according to Michael Barrier on his commentary on "Fast and Furry-ous" which can be seen on the first LTGC DVD release.)
Bobby Bickert
"Gremlins from the Kremlin">>>"Russian Rhapsody"

"It Hopped One Night">>>"One Froggy Evening"
The Rabid Rabbit= Hot Cross Bunny
(from the animation draft Devon Baxter posted on Cartoon Research.)
"With all respect to the great mousetrap."- Popeye, "The Spinach Overture" (1935)
Bobby Bickert
The following are taken from Jeff Lenburg's Encyclopedia of Animated Cartoon Series, which is notorious for its mistakes, so they may not be accurate:

"Strange Innertube">>>"Innertube Antics"

"The Shooting of Dan McScrew">>>"The Shooting of Dan McGoo"

Forgot to Duck >>> Canvas Back Duck

Sweatin' Bullets >>> Home on the Range

Family Guy

An American Dog in Paris >>> We Love You, Conrad

Famiry Guy >>> Tiegs for Two

All in the Nielsen Family >>> Ratings Guy

Jesus Christ! >>> Jesus, Mary and Joseph!

Stand Your Brown >>> A Shot in the Dark

My Little Pony: Friendship is Magic

Fluster-shy >>> Stare Master

Sissy Fit >>> Sisterhooves Social

Cutie Markless >>> The Cutie Map

The Simpsons

Fat Man and Little Boy >>> Thirty Minutes Over Tokyo

I Only Have My Eyes for You >>> Specs and the City
From the "1997 Disney Day to Day Calendar" and "The Ultimate Disney Trivia Book 3":

"Two Fabulous Characters" >>> "The Adventures of Ichabod and Mr. Toad".
Just Mickey (This title is used in the Treasures release) >>> Fiddling Around