2x Rare (or higher rarity) Cards
You don't want a hand full of uninkables and nothing to play, so you have to be careful about what you throw away and what you keep in your opening hand
While Cinderella works especially well in decks that focus more heavily on princess characters, she also does let you trigger her effect by just playing her, making her a solid draw/ink engine in-and-of-herself
Notably, Dark-Dwellers does not interact favorably with counterspells, so you should avoid them as much as possible
The same fate, sadly, has befallen Ultima Weapon
Not all of the ones you buy are available to use in competition play, but all of them will look awesome in your collection