Some editions include several works that were not completely of Shakespeare's authorship (collaborative writings), such as The Two Noble Kinsmen, which was a collaboration with John Fletcher; Pericles, Prince of Tyre, the first two acts of which were likely written by George Wilkins; or Edward III, whose authorship is disputed.
These plays are generally classed into 3 main categories: histories, tragedies and comedies.
The Complete Works (especially in older editions) are often sought after by book collectors, and a number of binderies and publishing houses have produced leather bound and gilded releases for luxury book collecting.
Both mainstream and academic publishing companies have released multiple editions and versions of their own collections of Shakespeare's work, often updated periodically.
(For instance, the Complete Works published by the Arden company is often referred to as the Arden Shakespeare, and the edition produced by Yale University called the Yale Shakespeare.)