If/guide

Gear (はぐるま)
Needle Field → interact with the Gear.

Eyeball / Eye lumps (めだま)
Starry World → interact with the eye NPC.

UFO
Starry World → Square Brick Path → Old Street → UFO → UFO Playground → interact with the alien.

Naginata (なぎなた)
Circuit Maze → Geometry World → Circuit Maze B → interact with the Naginata.

Ninja (にんじゃ)
Starry World → Paint World → Toy Box → Clusteramaryllis World → Paper Windmill Path → Japanese Castle → interact with the ninja hiding in the wall.

Squirrel (りす)
Dark World → Train Station A → City → interact with the Squirrel.

Waveform (はけい)
Needle Field → Chaser Place → Neon Path → Red Street → Dark Maze → interact with the waveform monitor.

Noise (ノイズ)
Needle Field → Chaser Place → Neon Path → Red Street → Dark Maze → Monochrome A → interact with the noise shadow.

Junk (ジャンク)
Needle Field → Chaser Place → Neon Path → Red Street → Dark Maze → Monochrome A → Monochrome B → FC World → FC Dungeon → Apartment → enter the last room.

Ice (こおり)
Crazy World → Snow World → Red Houses → enter the second house from the right repeatedly until a blue NPC appears → Crystal Maze → Ice Castle → sit on the chair repeatedly until the pathway appear a blue dot → Ice Castle B → go to the top.

Suminuki (すみぬき)
Circuit Maze → Geometry World → Green Block Path → Man Symbol Maze → Monochrome C → Gray Wasteland → Monochrome Flower Garden → interact with the monochrome girl.

Kikyou (ききょう)
Needle Field → Chaser Place → Neon Path → Red Street → Dark Maze → Monochrome A → Monochrome B → FC World → FC Dungeon → Villa → interact with the flower on the desk.

Perfume (こうすい)
Crazy World → Snow World → Red Houses → enter the second house from the right repeatedly until the blue NPC appears → Crystal Maze → interact with the perfume.

Floor Lamp (スタンド)
Crazy World → interact with the lamp.

Matching (おそろい)
Dark World → Train Station A → City → Train Station B → Apple Trees Forest → Laughing Face Area → interact with the block.