Trying to classify beer is a difficult task, a little like classifying soccer players into groups of forwards, strikers, wingers, midfielders, defenders etc...

And let’s not forget that at the heart of matters there are two basic schools of thought which distinguish between top and bottom fermentation.

Top fermentation
Ale Mild Ale, Bitter, Brown Ale, Cream Ale, Pale Ale, Strong Ale, Old Ale, Birra d’abbazia, Abdijbier, Trappiste, Bière de Garde, Barley Wine, Kölsch
Stout Imperial Stout, Oatmeal Stout, Steambeer
Porter
Weizen Weissbier, Bière Blanche, Witbier, Dunkelweizen, Faro, Lambic, Gueze, Kriek, Weizenbock
Bottom fermentation
Lager Kellerbier, Strong Lager, Münchner, Dunkel,
Rauchbier, Schwarzbier
Pils, Pilsner, Pilsener, Light Pils
Bock Doppelbock, Maibock, Eisbock, Ice Beer