My list of "never brewed" is pretty long, but it would be a lot longer if not for the Master Homebrew Program, which forces you to brew outside your comfort zone to rank up. My current list is by BJCP category, asterisk means on list to brew this year:
Cat 3 - Czech Pale Lager *
Cat 5 - German Leichtbier
Cat 9 - Dopplebock *, Eisbock, Baltic Porter
Cat 10 - Dunkles Weissbier
Cat 12 - Australian Sparkling Ale
Cat 14 - Scottish Light, Scottish Heavy
Cat 15 - Irish Extra Stout
Cat 16 - Sweet Stout, Tropical Stout, Foreign Extra Stout
Cat 17 - British Strong, Old Ale, English Barleywine
Cat 20 - Imperial Stout
Cat 21B - Belgian IPA, Red IPA, White IPA, Rye IPA, Brut IPA
Cat 22 - American Strong, American Barleywine, Wheatwine
Cat 23 - No Euro Sours except Gose
Cat 25 - Belgian Golden Strong
Cat 26 - Belgian Dubbel, Belgian Tripel, Belgian Dark Strong
Cat 27 - Lichtenhainer, London Brown, Piwo Grodziskie, Roggenbier. Sahti
Cat 28 - Brett beer, Mixed Ferm Sour, Wild Specialty, Straight Sour *
Cat 29 - Fruit & Spice Beer, Specialty Fruit beer, Grape Ale
Cat 30 - Speciality Spiced Beer.
Cat 31 - Alternate Grain, Alternate Sugar
Cat 32 - Specialty Smoked
Cat 33 - Specialty Wood Aged
Cat 34 - Clone beer, Mixed Style, Experimental
Cat X - Dorada Pampeana, Argentia IPA, Italian Grape,