There are many Irregular Verbs in English which do not conform to the pattern. The principal parts of the English verb are the base form, the simple past, and the past participle. For regular verbs, the simple past and the past participle are spelled the same and are created by adding ed to the base form. However, there are many irregular verbs in English which do not conform to this pattern.
The additional forms of the verb in English are the s form (3rd person singular present), and the present participle, which is created by adding ing to the base form. There are no irregular forms of the present participle, so the spelling of any verb will adhere to the rules of spelling for regular inflection.
A comprehensive list of English irregular verbs, including their base form, past simple, past participle and definitions is here below.