Motorcycle
Can be found in Garden World from the hub then go down a little bit and to the left. Similar to Madotsuki's bicycle, allows you to move twice as fast, you will be using this A LOT in your adventures.
Boy
Can be found in Geometry World from the hub.
Chainsaw
Can be found in Grave World from the hub. Go up till you see the spade and then to the right until you see a giant heart vomiting. Go through the hole and you will notice the map change and the music will soften. From here go to the left and look for a door on the wall to enter The Hospital. Now continue going left to reach a door. Go through this and keep going until you reach the very end of the corridor. In this room there will be three doors go in the far right one and go through the left door twice. From here follow the path until it turns North, instead go south and you should see a red spot on your left. Ride over it and you will be teleported to a new area. In here go through the green club looking things and you'll run into the chainsaw sooner or later. Similar to Madotsuki's knife, this can be used to kill enemies/destroy objects and walls, another very useful effect.
Lantern
Can be found in Forest World from the hub. Go left and AS SOON as you see the bench go straight down. You'll see a hole in the ground, go around the cones and fall in. From here go down, right, up, right, immediate down, second right, up, right, the lantern will be on the far wall. Similar to Madotsuki's Lamp, this can be used to light up dark areas and has a few other special uses too. Also catches some characters on fire.
Fairy
Note: Dangerous Route! Use Motorcycle
Can be found in Gravel Maze World from the hub. Go straight right then up as soon as you exit the path and keep going until you see a taxi and press z in front of the passengers seat to reach The Highway. From here just keep going right until you reach a forested area, it will take awhile. Now go down then right to see a dark robot, you must pass directly in front of him or he will block the way then just go right into the trees to go to the next area. Here just talk to the fairy to get the effect. This can be used to get into small areas and Urotsuki does a spin if you press z. Also can be sometimes used to pass over small gaps.
Spacesuit
Can be found in Marijuana Goddess World. Go straight up until you see the grey blob things then go left until you see a giant pink door. Go in and go down into the next room. Go right and go up the stairs. Keep going right then go down the stairs and to the left into the next room. Continue going left until you reach a ladder, go up it to enter Japan Town. Keep going left until you see a red mailbox. Press z in front of it to go to the Museum. Go right, down, then down again to enter the Factory. go in the middle door then go down then right past the first door and into the second door, go in there. Now go in the right again and you should see the spacesuit below you. This can be used to float across gaps and is required to move around in some areas like space. (durrhurr)
Glasses
Found in the museum. They can be used to see things not visible without them.
Rainbow
Wolf
Medabomb
Like the Medamaude fomr Yume Nikki, it sends you back to the main hub.
Telephone
Miko
Penguin
Bug
Spring
Invisible
Cripple
Tall
Cactus
Cake
Child