I was watching LiquidWifi's playthrough of the Randomizer Mod, when I noticed that a lot of the Stage Messages that appeared were unused, and a lot of these are not documented. I'll lost them below, along with theories as to they're use. Please note that there are a few which may be used, but I don't know about. If there are, tell me.
FIND HANS MOLEMAN
This would have been used in Level 4-Mission 4, Return Of The Nearly Dead. The final mission instead just directs the player to the Cemetery.
FIND APU AT THE KWIK-E-MART
This could have been used in a multitude of missions, the most prominent being Level 4-Mission 7, From Outer Space. The final game instead tells the player to enter the Kwik-E-Mart.
STREET RACE
Something relating to Street Races.
DRIVE THE WASTE TO THE ALIEN SHIP
Alternate text for the Nuclear Waste delivery missions. The final game uses the "DRIVE TO THE SCHOOL PLAYGROUND" text.
FIND THE ARMORED CAR
Alternate text for Level 5-Mission 6, Kwik Cash. Both stages before and after evading Chief Wiggum use the more descriptive "DRIVE TO THE GOOGLEPLEX" message in some variation.
FIND APU
Could be used in multiple missions. Should the player ever need to talk to Apu, the game first sends the player to Apu's location instead of making the player find him.
ENTER CLETUS' TRUCK
This would have been used in the missions where the player is forced to drive Cletus' Pickup Truck. The player would have to get into the vehicle manually instead of being automatically placed into it.
TAKE THE LASER TO THE SQUIDPORT
Would be used at some point in Level 6, probably after Bart obtains the Laser Gun in Mission 4, Duff For Me, Duff For You. This could mean that the Mission Full Metal Jackass would originally involve Skinner intercepting Bart.
FIND CHIEF WIGGUM
Would be used when the player has to find Chief Wiggum, such as in Level 4-Mission 1, For A Few Donuts More, or Level 5-Mission 4, This Little Piggy. A follow sequence and a collect items sequence were added to these missions respectively to make them longer.
DRIVE TO THE GAS STATION
The player never has to drive to a Gas Station. This could have at one point been used in Level 1's Bonus Mission, This Old Shanty, as Cletus mentions driving to the Gas Station in the mission's opening dialogue.
DRIVE TO THE KRUSTY BURGER BY THE POLICE STATION
The player never has to drive here.
WIN THE RACE
Could have been used in any of the game's races, including Street Races. It was replaced with more descriptive text.
GET TO GRAMPA FIRST
Would have been used in Level 4-Mission 4, Return Of The Nearly Dead. This seems to describe an alternate plot for the mission, as in the final, you are racing Chief Wiggum there before he locks up the Retirement Castle for the night. It could also just be a miss-interpretation of the mission's goal on the writer's part, given that you're racing there so that you can talk to Grampa.
TIME TRIAL
Related to Milhouse's Time Trial Street Races, or possibly Wager Races.
TAKE THE NUCLEAR WASTE TO THE ALIEN SHIP AT THE SCHOOL
More alternate text for the Nuclear Waste delivery missions.
COLLECT THE EVIDENCE
Would have been used in the Level 6 Bonus Mission, after destroying Chief Wiggum's vehicle. No stage message is displayed in the final game.
FIND THE KETCHUP
Alternate text for the first stage of Level 4-Mission 3, Ketchup Logic. The "find" part of the text suggests that the Ketchup was originally spread out, and wasn't a linear trail, as in the mission Monkey See, Monkey D'oh, which also used "find" in it's text for collecting the Monkeys.
RACE THE ALIEN CAR TO THE NUCLEAR WASTE
This could have been used in Level 7-Mission 7, Alien "Auto" Topsy Part III, where the player must race the Alien Car to the Power Plant. It may also have been used in the early version of said mission as listed in the PR Asset Discs, where the player would have to race the Alien Car to the Nuclear Waste.
DESTROY THE LASER CRATES
Would probably have been somehow used in Level 6-Mission 4, Duff For Me, Duff For You.
FIND MR. BURNS
Could have been used in the early version of Level 1-Mission 7, The Fat and Furious, where Homer would have to enter Mr. Burns' Mansion to find Burns, or in the pre-mission of Level 7-Mission 5, Alien "Auto" Topsy Part I.
DESTROY THE BLACK CAR
Could have been used in Level 7, relating to a mission which would involve destroying an Alien Car.
FOLLOW KRUSTY'S LIMO
Would have been used in Level 6-Mission 2, Getting Down With The Clown, as indicated by said mission's PR Asset Disc description and final game mission briefing screen.
GET INTO A VEHICLE
Was replaced with "GET INTO YOUR VEHICLE".
DRIVE TO THE HOSPITAL ENTRANCE
May have been used in Level 5-Mission 3, ... And Baby Makes Eight, as the Nonuoplets Minivan is located in the Hospital's Entrance.
STEAL BOARDS FROM CLETUS
Would have been used in Level 7-Mission 1, Rigor Motors, which contains a portion of the mission dedicated to stealing Boards from Cletus' house. The final game used "DRIVE TO CLETUS' HOUSE" and "COLLECT THE BOARDS" when driving to his house and reaching his house respectively. This would explain why the Boards are loaded as an object during the "DRIVE TO CLETUS' HOUSE" objective.
CROSS THE FINISH LINE BEFORE TIME RUNS OUT
Would logically have been used in Wager Races.
GO OUTSIDE
Was replaced with text describing the next objective; the game never dedicates an objective towards exiting an Interior.
COLLECT THE KRUSTY BURGER MEAL
Would have been used in Level 3's Bonus Mission, Princi-Pal, as a part of said mission envolves collecting some dinner from a Krusty Burger for Skinner.
FIND CAFFEINE PILLS TO WAKE GRAMPA UP
Would have been used in Level 4-Mission 5, Wolves Stole My Pills, when collecting Pills to wake Abe up. The game uses "ENTER THE KWIK-E-MART" and "COLLECT THE CAFFEINE PILLS" instead.