Oh....I just thought of it since I use some of these cards in my Yubel deck. Not sure what cards to take out yet though.
Add in(s)
Monster Reincarnation <-- (We know what this does already don't we? xD)
Dark Grepher +1 or 2 <-- (Discard 1 Lvl 5 or higher monster to special summon this card. You can send one dark monster in your hand to the grave to send one monster in your deck to the graveyard.)
The Beginning of the End <-- (Best way really. If you have 7 or more dark monsters in your
grave, remove 5 of them from play to draw 3 cards.)
Dark Bribe / Solemn Judgement <-- (-cough-)
Spirit Reaper <-- (-cough again)
Dark Eruption <-- (Add one dark monster with 1500 or less atk points from your graveyard to your hand)
Dark Hunter <-- (This card effect changes based on the number of dark monsters in your graveyard. 1: Loses 400 atk. 2-4: Gains 400 atk. 5+: You can send this card from the field to the graveyard to destroy all defense positions monsters your opponent controls.)
Dark Illusion <-- (Pretty much like Solemn Judgement except it works for Dark monsters)
Escape from the Dark Dimension <-- (Special summon one of your removed from play Dark Monsters. When this card is removed from the field, destroy the monster.)
Doomsday Horror <-- (Works well with the "Beginning of the End" Atk and Def are equal to the # of dark monsters removed from play. When sent to the graveyard, return all removed from play dark monsters to the graveyards.
Veil of Darkness <-- (During your draw phase, if you draw a dark monster, you can reveal it and send it to the grave to draw 1 more card)
Note(s): Well these are some cards I'm giving you that could help out the deck a bit
Taking out
Not sure what to take out yet. I'll think about it for a bit.