mtg card avacyn Magic The Gathering - Archangel // Avacyn, The Purifier (005/297) transform Archangel Avacyn at the beginning of the next upkeep Avacyn Restored Draft Booster Pack

There isn't any good direct comparison to Mangara's abilities, but the closest thing that popped into my head is Runic Armasaur, another creature whose card drawing ability is entirely dependent on your opponents' actions, making the card inconsistent where it sometimes draws you zero cards and sometimes floods you with card draw

One opponent decides not to pay the one and tries to justify it with "well, it's only one card", and the pact is broken

Okay baseline, exciting ceiling, and the extra density for storm solidifies this as a must add if you support storm in your cube

Finally, a Location-focused deck can get a lot of value from a well-timed Jim Hawkins - Space Traveler