While trying to come up with a good Rainbow Neos build, it kinda deviated to this. It's a fun, but generally non-competitive deck to relax with.
A lot of the Dark monsters are interchangeable, really. The point is to have as many different Dark monsters as possible milled by Magical Merchant and other means. Once milled, Rainbow Dark Dragon swoops in for the kill.
Clearing the field is simple. Black Salvo + Dekoichi or Blast Sphere to Black Rose Dragon, or Swords of Concealing Light to Dark Hunter for monsters and Giant Trunade for Spells and Traps.
Cards I'm considering: Ryko, Veil of Darkness