Types of Magical People
"Metamorphmagi are really rare, they're born, not made."
-- Nymphadora Tonks
Some magical folk have special powers which allow them to do things most Wizards can't do. These magical abilities can be learned in some cases, such as the complicated magic required to become an Animagus. Other such abilities cannot be learned; the Wizard must be born with the powers.
An Animagus can change into the form of an animal. The magic for this transformation is complicated and very advanced, and very few wizards even attempt it. When a wizard transforms into his or her animal form, some visual clue typically connects that form to the human. For example, McGonagall and Skeeter both wear glasses and their Animagi forms include marks around the eyes. See Animagi.
An Arithmancer is a person who is an expert on Arithmancy. The word is a combination of the Greek words "arithmetike," which means "of numbers," and "manteia," which means "divination."
A Legilimens is a Wizard who has learned the art of Legilimency, sensing the thoughts of another person. Dumbledore and Snape are both experts at this form of magic. Voldemort is also an accomplished Legilimens.
Unlike some of the other types listed here, Metamorphmagi are born with the ability to change their appearance at will. Nymphadora Tonks is a Metamorphmagus. The word comes from the Greek prefex "meta-" connotating change, "morph" meaning "form," and "magus" meaning "wizard."
The skill of Occlumency allows a person to block the efforts of a Legilimens to probe their thoughts and memories. A person who practiced that rare skill is called an Occlumens.
Another rare gift is the Inner Eye, the ability to prophesy. A wizard with this gift is called a Seer. Trelawney does have some small measure of this talent, but it has surfaced only twice that we know of. She is, however, the great-great-granddaughter of a very famous and very talented Seer, Cassandra Trelawney.