Can the President of the United States pardon everyone? For example, let's say a criminal organisation is committing crimes, after awhile they get raided by the police, everyone gets arrested and convicted, can the president of the US pardon everyone in that organisation?
The President can pardon everyone (with the possible exception of himself) of crimes, and can pardon people by category rather than by name.
But, the President can only pardon federal crimes that have been committed and are mentioned in the pardon. However, the federal crimes do not have to have resulted in convictions or even charges to be pardonable.
Many mass pardons of this type were made after the U.S. Civil War. Another notable mass pardon was of draft dodgers after the Vietnam War was over by President Carter.
The President cannot (in the opinion of many, it hasn't been authoritatively resolved) pardon himself. The President cannot pardon a state or local crime or a crime against the law of another country. The President cannot use the pardon power to eliminate the right of one person to sue another person. The President cannot pardon a crime that was not committed at the time that the pardon was issued.