Based on this post and your "Knuckle-Busting Card Magic" thread, I think you might have slightly confused the definitions of the terms "move" and "effect". A pass is not an effect, it's a move that you would use to achieve an effect. So, for example, in the context of an Ambitious Card Routine, you might execute a pass to achieve the effect of the card jumping to the top of the deck. I suppose a simple way of explaining the difference is this: The performer does moves, the audience sees effects.
So, if you're talking about what moves are essential in card magic then yes, a couple of variants of the pass are always good to have, plus some alternative controls like the spread cull, jog shuffle and side steal. Then developing on from the side steal, it's good to get some other palming down, so a good top palm and a bottom palm could be added in. Then if you also have one or two good forces, a multiple lift that you're comfortable then your set to go for most classic card effects.
If, however, you are talking about effects, then "You pick a card and I find it" is the most tried and tested plot in all magic (even more so, I'd wager than "You have a coin behind your ear"), so you could do with having a personalised way of presenting that. Ambitious Card is a logical development from that idea, but after that you'd probably want to get away from things using a selected card, so I'd recommend learning a four ace trick of some sort (an assembly, spectator cuts the aces, Twisting the Aces, something like that). In real life, if you had those three tricks down, rehearsed to perfection and with an interesting and engaging presentation, you'd have a pretty good walk-around set.
