A particularly good source for case law. State reported cases back to 1950, Federal circuit/district reported cases back to 1923. U.S. Supreme Court cases from 1791. Unreported coverage varies.
Dockets list the pleadings and motions filed in a case, as well as court orders. Some online dockets contain full text of the documents filed. A docket is essential to keep track of a case you are involved in, but can also be used to find sample pleadings and motions. Dockets can be searched to see if someone was a party in a civil or criminal case.