According to the DSM-4 (if you're inclined to accept it as valid, 200, APA) there are 10 PDs, that are clustered into 3 groups, A, B, & C. The Cluster A PDs are Schizoid, Schyzotypal, and Paranoid.
Here is some more info:
Types of Personality Disorders
There are many formally identified personality disorders, each with their own set of behaviors and symptoms. Many of these fall into three different categories or clusters:
1.) Cluster A: Odd or eccentric behavior
2.) Cluster B: Dramatic, emotional or erratic behavior
3.) Cluster C: Anxious fearful behavior
Since there are too many identified types of personality disorders to explain in this context, we will only review a few in each cluster.
Cluster A:
Schizoid Personality Disorder
Schizoid personalities are introverted, withdrawn, solitary, emotionally cold, and distant. They are often absorbed with their own thoughts and feelings and are fearful of closeness and intimacy with others. For example, a person suffering from schizoid personality is more of a daydreamer than a practical action taker.
Paranoid Personality Disorder
The essential feature for this type of personality disorder is interpreting the actions of others as deliberately threatening or demeaning. People with paranoid personality disorder are untrusting, unforgiving, and prone to angry or aggressive outbursts without justification because they perceive others as unfaithful, disloyal, condescending or deceitful. This type of person may also be jealous, guarded, secretive, and scheming, and may appear to be emotionally cold or excessively serious.
Schizotypal Personality Disorder
A pattern of peculiarities best describes those with schizotypal personality disorder. People may have odd or eccentric manners of speaking or dressing. Strange, outlandish or paranoid beliefs and thoughts are common. People with schizotypal personality disorder have difficulties forming relationships and experience extreme anxiety in social situations. They may react inappropriately or not react at all during a conversation or they may talk to themselves. They also display signs of magical thinking by saying they can see into the future or read other peoples minds.