Since the past tense and part participle of the verb needboth end with -ed and the third person singular ends with -s only, the verb need is a regular verb.
"Have" is an irregular verb in English.
It's irregular.
regular or irregular
It's an irregular verb.
It's an irregular verb.
To swim is an irregular verb.
It's an irregular verb.
It's an irregular verb.
Ate is an irregular verb.
irregular
irregular
By is not a verb, so it is neither regular nor irregular.