Passenger Ferry

For three generic mana you get a 4/3 attacker cheap enough to crew off a single two-power creature or a pair of one-drops, but the body is the setup, not the payoff. The real ability is the blue tax on attack: pay one blue and you can hand unblockable to a different attacker for the turn, which turns the Vehicle into a repeatable evasion engine for whatever threat actually matters. That indirection is the whole design. It does not push its own 4/3 through; it clears a lane for the creature you would rather connect with, whether that is something carrying an aura, a commander that wants to deal combat damage, or a heavy hitter the defender has been holding blockers for. Because the effect keys off attacking rather than casting, it dodges the counterspell that punishes a dedicated unblockable spell, and it recurs every combat as long as the Vehicle keeps swinging. The blue payment is optional and the target is another attacking creature, so it wants a wide-ish board to point at rather than a single-creature deck. What makes it more than filler is the split between a colorless crew cost and a blue payment on attack: any deck can field it, but only a blue deck unlocks the part that reads.