One I would have thought was not protected by the 1st Amendment would have been hate literature. Wrong. Hate is protected. So is something like treason unless it incites violence.
The things that fall outside protection by the 1st Amendment are Unsuitable pictures of children Violence or the true threat of violence. Obscenity (obviously it has not been enforced. Or it's been tried and failed). defamation
These and not rigid exceptions. There are tests to determine if something is or is not protected by the first amendment.