Edit: After looking back through the book, the answer is most likely Elves. "Mechanicals" are a type of worker in A Midsummer Night's Dream, and there are definitely royals and lovers.
<em>A Midsummer Night's Dream</em> is a play originally written by William Shakespeare. This story describes the confusing and comical interactions that take place between a group of young Athenians and the fairies and creatures that inhabit the forest. Lovers, royals and mechanicals appear in the story. However, elves do not.