I put a bunch of cards together that I like or inspire me. There are no themes. Number of cards per color or color pair are consistent. No thought went into colored pips. Mana curves by color are roughly focused on 2 drops, the cube probably skews toward control/piles because of the talismans and fixing. Creature/spell density follows Maro's skeleton rules by color (white 62% creatures, blue 50/50 split, etc.)
Special design rule was no overlap with my aggro cube; lots of these inclusions are from its cutting room floor.