There are 24 effects that the player can find, each of which affects Madotsuki's appearance and often abilities. Very few players achieve the goal of gathering all effects alone, and walkthroughs exist mainly to help find each one.
Effects
Frog
Madotsuki's head becomes that of a frog. Using this effect makes Madotsuki move faster in water. Pressing '1' makes her hop once.
Umbrella
Getting out the umbrella causes it to rain. Even upon putting the umbrella away, it will continue to rain. Pressing '1' twirls the umbrella. Rain is good for putting out large fires.
Hat and Scarf
The hat and scarf is exactly as it sounds. However, pressing '1' while it is snowing turns Madotsuki into a snowman and back.
Yuki-onna
Equipping this effect causes it to immediately snow.
Knife
Madotsuki holds a kitchen knife in her hand. Using this effect results in her stabbing whatever is in front of her. Pressing '1' makes her change the hand she is holding the knife with.
Medamaude
After transforming into this odd creature, pressing '1' allows instant return to the door room.
Fat
Doubling in size grants Madotsuki the ability to jiggle her fat around by pressing '1'.
Midget
This makes Madotsuki much smaller. This conveniently allows her to enter the hole on Mars. Pressing '1' adds a midget clone to the party and '3' will cause one to spontaneously explode.
Flute
Madotsuki holds a flute to her lips. Pressing '1' makes her play a short tune with a random pitch. Doing this rapidly, in quick succession, makes a rather melodious song. It is found in the mall.
Neon
Becoming a sentient neon light certainly has its advantages. '1' will make the screen change colors. The color change fades once neon is unequipped.
Nopperabou
Madotsuki loses her facial features with this effect. Furthermore, pressing '1' causes her head to temporarily remove itself from her shoulders and rotate 360 degrees.
Severed Head
Madotsuki loses her body. She can still crawl around with just her head, but this reduces her speed to almost nothing. It is the slowest effect in the game.
Towel
After donning this fashionable item, pressing '1' causes a sneeze.
Cat
Half human and half cat, Madotsuki becomes quite charming to the denizens of her mind. Pressing '1' causes her to meow and everyone in the area to approach her slightly.
Lamp
Madotsuki's head is replaced by a lamp; '1' will toggle its state. Sight becomes much easier with a light. In fact, certain things--strange patterns on the ground in dark areas, for example--can not be seen without one.
Bicycle
Madotsuki rides a bicycle. It dramatically increases speed. Madotsuki cannot get into beds when this effect is on. Pressing '1' makes the bicycle's bell ring.
Long Hair
This effect apparently serves only the purposes of vanity.
Poop Hair
Poop hair, while a questionable hairstyle, can be quite useful. Pressing '1' creates a fly (maximum of eight) to hover in place. They can be used as markers, probably to prevent getting lost. The flies are persistent through effect changes.
Blonde Hair
Like long hair, this apparently is only a new hairstyle.
Triangle Kerchief
This effect, styled as a tiara, grants Madotsuki the ability to become ethereal after pressing '1'. In this form the Toriningen are unable to transport her to a dead-end area without her consent.
Witch
Madotsuki dresses up like a witch. Can be used in the department store to start a flying minigame.
Demon
Madotsuki becomes a horned monster using this effect. While it is raining, pressing '1' causes a lightning strike.
Buyo Buyo
This effect causes Madotsuki to become seemingly gelatinous. It is apparent while walking and especially after pressing '1' which causes her to jiggle around.
Stoplight
After becoming a stoplight, pressing '1' toggles between red and green states. While red, dream inhabitants obey and become still. Monoko reacts further, however. After stopping, Monoko transforms into the 5-armed girl.
Instructions
The only effect you start with. They briefly explain how to play the game.
Pseudo-effects
Chair
By sitting at Madotsuki's desk in the dreamworld and pressing 'Z', Madotsuki can pull the chair away and start to hop around on it. This is very slow and grants no extra abilities, although it does change her appearance. It possible to equip the bicycle effect immediately after sitting in the chair; this will cause a glitch that doubles the speed of the bicycle until it is dismounted.