The only card to note here is Snapcaster MageSnapcaster Mage, since when coupled with Time WarpTime Warp, you can cast it at least one more time out of the graveyard
Those numbers are also perfect for balancing the color distribution of the Cube, and it allowed me to create my next restriction
Between the fast Special Summoning, Cyberse synergy, and Link Monster action, you wont be able to tell where the technology ends and the magic begins
Pendulum Effect You can target 1 other Spell/Trap Card on the field
Of course, both Gengar ex and Mewtwo ex use a lot of energy for their primary attacks, and most players won't have time to ramp up without a Gardevoir available
If that is the case, a Starter Deck obviously won't give you the full potential of said synergy, but you can at least get an idea of how the gameplay feels, or whether certain cards are the building blocks you thought they were