I had this idea where, basically, 2 of each type of mini-game from each game would return in a section of the mini-games called "Retro Mini-Games", and the new mini-games would be "New Mini-Games". You can also turn off the Retro Mini-Games from appearing in the Party Mode. Here are all my ideas:
4-P Mini-Games
Bumper Balls
Shy Guy Says
Honeycomb Havoc
Sneak n' Snore
Parasol Plummet
Cheep Cheep Chase
Booksquirm
Slime Time
Hotel Goomba
Coney Island
Smashdance
Lift Leapers
Track & Yield
Ghost in the Hall
Grin and Bar It (edited for 4 players)
Sick and Twisted
Speedy Graffiti
Hedge Honcho (works well with the Wii Remote pointer)
Dust Buddies
1-vs-3 Mini-Games
Piranha's Pursuit
Tug o' War (shaking the Wii Remote instead of spinning the Control Stick?)
Quicksand Cache
Look Away
Hide and Sneak
Ridiculous Relay
Hide and Go BOOM!
Money Belts
Curvy Curbs
Mathletes
Pop Star
Dust 'Til Dawn
Balloonatic
Flashfright
Synch-row-nicity (the one player can't "synchronize" with anyone but the 3 players can "synchronize" with each other)
Power Trip
Thrash 'n' Crash
Fast Food Frenzy (the Wii Remote pointer would work well here as well, with different buttons causing different food items to drop onto the conveyor belt)
Nothing to Luge (perhaps twisting the Wii Remote would control the turning)
2-vs-2 Mini-Games
Bombsketball
Desert Dash
Destruction Duet
Cake Factory
Log Jam
Pump, Pump and Away
Dungeon Duos
Pair-a-Sailing
Banking Coins
Submarathon
Pixel Perfect
Rocky Road
Buzzstormer (twisting the Wii Remote for turning)
Pyramid Scheme
Rope a Dope
Sugar Rush
Boo-ting Gallery
Airbrushers (shaking the Wii Remote would cause you to flap)
Shorty Scorers
Duel Mini-Games
Ground Pound (each person has their own set of logs)
Teetering Towers (each person has their own screen of towers)
Mushroom Brew
Psychic Safari
Vine with Me
End of the Line
Kareening Koopas
Bowser Wrestling
Button Mashers
Pound Peril
Cog Jog
Something's Amist
Weight for It
Camp Ukiki
Unhappy Trails (no dividing rope this time, each person is by their self)
Balancing Act
Loco Motives
Trash Landing (point at the screen to select a rope)
Cucumberjacks (pushing and pulling the Wii Remote would "saw" the cucumber)
Battle Mini-Games
Mushroom Mix-up
Face Lift (pointing at the screen would work well to change Bowser's face)
Bumper Balloon Cars
Day at the Races (more selection)
Merry-Go-Chomp
Locked Out
Chain Chomp Fever
Trace Race
Astro-Logical
Random Ride
Insectiride
Wrasslin' Rapids
Monty's Revenge
The Final Countdown
Gimme a Brake (edited for 4 people)
Cut from the Team
Glacial Meltdown
Cheep Chump
Globe Gunners
Rare Mini-Games
Slot Car Derby
Driver's Ed
Mario's Puzzle Party
Dizzy Dinghies
Game Guy's Lucky 7
Game Guy's Roulette
Game Guy's Sweet Surprise
Bob-omb Breakers
Doors of Doom
Piece Out
Block Star
Seer Terror
Lab Brats
Ice Moves
Stick and Spin
Pour to Score
Puzzle Pillars
Focus Mode Triangle Twisters
Frenzy Mode Triangle Twisters
Banana Mini-Games (run by Diddy Kong)
Banana Punch (versus Diddy Kong, whoever gets more bananas wins)
Da Vine Climb
Mass A-peel (versus Diddy Kong, whoever gets more bananas wins)
Tally Me Banana (versus Diddy Kong, whoever gets more bananas wins)
Banana Shake
Pier Factor
Jump, Man (versus Diddy Kong)
Vine Country (versus Diddy Kong)
A Bridge Too Short (versus Diddy Kong)
Peel Out
Bananas Faster
Stump Change
Graffiti Mini-Games (run by Bowser Jr.)
Cage-in Cookin'
Rain of Fire
Scaldin' Cauldron
Pit Boss
Dizzy Rotisserie
Dark 'n Crispy
Slot-O-Whirl!
Treasure Dome!
Tunnel of Lava!
Funstacle Course!
Funderwall!
Magmagical Journey!
Comet Mini-Games (run by Rosalina)
Crane Game (from Mario Party 2, this time Rosalina is trying to get all of you!)
Cosmic Coaster
ID UFO
T-Minus Five (versus Rosalina)
Asteroad Rage (changed for 4 players)
Black Hole Boogie (changed for 4 players)
Lunar-tics (versus Rosalina)
Mass Meteor (versus Rosalina)
Saucer Swarm
Cosmic Slalom (versus Rosalina)
Ion the Prize (versus Rosalina)
Surf's Way Up (versus Rosalina)
Boss Mini-Games
Stardust Battle
The Final Battle! (the Koopa Kids are now Bowser Jr. and Kamek)
Frightmare
Bowser's Lovely Lift! (the Koopa Kid is now Bowser Jr.)
Superstar Showdown
Feed and Seed
Book Bash
Bowser's Block Party