Artifact Spacecraft When this Spacecraft enters, you may sacrifice a land or a Lander
Another one of my favorite examples, that is probably underappreciated outside of the Alpha context because its power is more subtle, are the Psychic Venom decks
This can make some items feel like a chore to obtain if you dont particularly favor one aspect like battling/collecting/etc
the despondency of the Reckless Cohort, who seems all too eager for an opportunity for self-sacrifice in the Battle for Zendikar
This isn't super exciting since we don't have many expensive things to ramp into, but it still makes two energy when it enters the battlefield, so even if we don't ever use it to make mana, it's still supporting our deck's theme and powering up our other cards
This makes Battlemager's Bracers a cheaper, more focused Rings of Brighthearth