Brands
Miller's flagship brands are (obviously) the Miller™ and Miller High Life® families of beer. Milwaukee's Best®, Magnum®, Meister Bräu, and Sharps® (a "non-alcoholic brew") also carry the Miller imprint. Henry Weinhard's, Hamm's, and Olde English became Miller brands in early 2000.
The Plank Road Brewery (brewers of Icehouse™, North Stone™, Red Dog™, and Southpaw™) is actually Milller using its original brewery name in order to look like a microbrewery. (Marketing. Sheesh.). Plank Road's company code is also 34100.
The Leinenkugel Brewery of Chippewa Falls, Wisconsin is an independent brewery purchased by Miller in 1988, but still run by managed by the Leinenkugel family. Leinenkugel's beers use a slightly more-detailed version of the Miller codes.
Mickey's Brewing Company is a front used to sell the Mickey's Malt Liquor brands that Miller purchased in 2000. If you're trying to date a Mickey's bottle older than that, you need to read about Stroh's dating codes.
All Löwenbräu beers sold in the United States are brewed & distributed by Miller (under license from Löwenbräu AG of Germany), and use the Miller coding system.
Skyy Blue malt beverage is also brewed by Miller.