"Should of known" makes no sense whatever, and is sloppy English especially when spoken. "I, you, he, she, should have known" is correct. Location: Arizona, U.S.
Simply so, should have knew or known?
Knowing or should have known fall under this rule, as it implies that there is an owed duty of care from one individual or entity to another. For instance, if a hazard led to an accident and the manager knew or should have known about the hazard, it creates liability for the accident.
Beside above, should be or should have been?
It is like “must” but weaker. Yet, it is stronger than “could.” Use “should have been” to express what you think should have happened, but did not happen. Often, you'll hear this phrase used in arguments or regrets about the past.
What is the known tense of had?
"knew" is past tense, "had known" is past perfect tense. Standard convention when writing is to use third-person past for the narrative.
Would have been usage?
The simple past just tells what happened. Past modals tell what could have, would have, and should have happened. To form these past modals, use could, would, or should followed by have, followed by a past participle verb. Use have for all pronouns; never use has or had to form a past modal.