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 → Music World → Old Street → UFO → UFO Playground → interact with the UFO.

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 World → Red Street → Dark Maze → interact with the waveform monitor.

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

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

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

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