Blanks are considered to be in the low tier of clacks, but I think CF has done some really cool stuff with blanks like the Julysicle and Oktoberfest. Just enjoy the artwork in the colors of the clack, think about that beer and popsicle sitting on your Esc 
you phrased that a little weird, but i'd be very hesitant to call oktoberfest a 'blank' since CC has actually made solid color keycaps.
'layered' would be more apropriate, but I think there was another 'brand name' for them already. in my head, I divide CC keycaps into:
blanks
bloodsplats
layers
leafs (although I think they're actually called 'toast')
skulls
wingnut/vader/66mhz/etc (these are all ultra rares and i think you just call them by name rather than category lol)
edited because rowdy was giving me the evil red eye....
If you want to categorize Clacks, I would suggest the following categorical rubrics:
Blanks - ESC
Blanks - Topre Fn
Blanks - Special: Julysicle, Candy Corn & Oktoberfest
Blanks - WASD & Arrow Clusters
Bloodsplats - ESC
Bloodsplats - WASD & Arrow Clusters
Skulls - single color
Skulls - Bi-color
Slulls - Tri-color
Skulls - translucent
420 - Bi-color
420 - Single Color
Special Clacks - Dark Lord, Gumrot, Gummyrot, etc.
Special Rare/ Limited Run - i.e., Wingnut (made for DT founders), GH Tri-color (made for tsangan), Ducks, 66mhz, etc.
Special Rare/ Prototypes - i.e., Mr. Friday prototype, etc.
