A projectile is any hitbox able to leave the user's damagable collision bubbles and move by itself, and most of them can be reflected. Ness' yoyo is also an exception, as it is not classified as a projectile despite its glitch. All non-item projectile attacks in Melee are special attacks and throws, usually neutral B. Common examples of projectiles include: Falco's laser (neutral B), Samus' missiles (forward B) and Young Link's bombs (down B). An example of a throw projectile is Mewtwo's forward throw, which launches multiple tiny Shadow Balls which can damage any character.
A majority of characters in Melee have at least one projectile attack; the characters that don't are Captain Falcon, Donkey Kong, Ganondorf, Jigglypuff, Marth, and Roy. It is considered a disadvantage to not have a projectile, because projectiles are very useful in setting up an approach.
All projectile attacks will not create a hit lag for the user. Most projectiles can be easily identified by attacking a metal box.
Number of Projectiles per Character
Note: This does not include Final Smashes.