During 1990 the American League had a combined total of six no hit games which is the most ever in a single season of play in Major League history.
On April 22, 1898, the National League had two no hit games on the same day which is the most ever in a single day of play in Major League history by one league. Nearly one-hundred years later; on June 29, 1990, the Major League record was tied, but not the single league record, when two no-hitters were tossed on the same evening (Dave Stewart: American League Oakland Athletics and Fernando Valenzuela: National League Los Angeles Dodgers).
Every single American League, National League, Union Association and American Association no hitter (along with many box scores) are listed on Baseball Almanac's pitching menu.