These are some of the cards I have considered for my Dark Deck. All cards are at the maxed number that I thought necessary. I only want it to be no more than 45 cards if at all possible.

Player
Dark Riku lvl 3

Dark Cards
Level 1
3x Shadow
3x Bouncywild
3x Soldier (L&D)

Level 2
3x Creeper Plant
3x Powerwild

Level 3
3x Barrel Spider
3x Large Body

Level 4
2x Stealth Sneak
1x Screwdiver

Level 5
1x Aquatank
1x Search Ghost
3x Behemoth
2x Invisible

Level 6
2x Darkball
3x Gargoyle

Level 7
3x Parasite Cage
2x Wizard

Level 8
1x Oogie Boogle
1x Captain Hook

Attack
3x Soul Eater
3x Divine Rose
1x Oblivion
1x Ultima Weapin

Magic
3x Fire
2x Gravity
2x Cura

Worlds
1x Disney Castle
1x Hundred Acre Woods
1x Wonderland lvl 2