The 12 bit constraint is a fun one although a little artificial. But picking 12 different colors with constant luminance is quite a challenge! ColorBrewer only

The 12 bit constraint is a fun one although a little artificial. But picking 12 different colors with constant luminance is quite a challenge! ColorBrewer only goes to 9, and to my eyes more than 6 is very hard to make out. But these 12 are quite nice if you don't mind a little blurring, particularly folks with some form of colorblindness.