Here are my categorization of skins (custom skins only). It's up to you how to sort on the wiki.
If authors have a different opinion after this is implemented, they can edit the wiki directly or leave a comment on this thread.
Light skins: SKBeeLite, Mondo! Bizu!, Candy Cane, Polar Bear Dreams, TouchLite (6 skins), Tundra Series (Aurora, Caribou Migration, Ice Floe, Summertime), MetroColours (light), Crimson Creme, Ebony & Ivory, Jistme the Bee, Jistme on the Outlook, A Sophisticated Bee, Tweakers.bee, King Penguin (King Penguin original, King Penguin toned down), Calcium, Dawn, Mondrian, A Brighter Bee, Mellow Blue, Clarity
Multi-Color skins: Wing-ated, WTF Skin
Dark skins: the rest