This my imaginary patch for Super Mario Maker.
Shake Koopas to create empty shells (in SMW, shake empty shell for Beach Koopa)
In SMB underground, underwater, and castle, Goombas now change color
In SMB3 underground and castle, object outlines now change color
New Effects: CRT, Game Boy, Grayscale, and Cycling Rainbow
New Tool: Paintbrush
Click on the paintbrush twice to open color selection menu, where you can change to many different colors like night backgrounds, gray SMB overworld, brown SMB3 underground, Green and Chocolate Grass in SMW, etc.
Now some things like Koopas, platform, and Lava Lift needed to use paintbrush to change color.
Paintbrush changes many things when you tap them using the paintbrush.
Mario: Change to Luigi (amiibo costumes and enemies swapped as well)
Pipes: Change color
Brick: Change to Throwable Block (In SMB, when Mario or a shell his it it flies away like when a vegetable bounces in SMB2 and can bounce off of enemies)
? Block: change to NSMB's Spiked ? Block (give Spiked ? Block wings for NSMB's winged ? block that moves back and forth)
Koopas: Change color (blue and yellow included in SMW as well)
Yoshi: Change color (In SMW using elemental colors and in NSMBU just appearance)
Hammer Bros. and Sledge Bros.: Change to Boomerang, Fire, and Ice
Fire Flower: Change to Ice and Gold Flower
P-Switch: Change to Silver P-Switch
Springboard - Change to SMB2J Green Springboard
Note Block: Change to SMB3's Warp Note Block
Bowser and Bowser Jr.: Change to SMB2J Impostor versions
Podoboo: Change to Fast Blue or Ice Podoboo
Piranha Plant: Change to SMB2J Red Piranha Plant (green in other styles)
Venus Fire Trap: Change to Venus Ice Trap
Firebar: Change to Icebar
Fire Koopa Clown Car: Change to Ice and Gold Koopa Clown Car
Magikoopa: Change to Fire and Ice Magikoopa
Lakitu: Change to Lakithunder