Evelyn, the Covetous

The crucial word in the ability is "each player's library," and that "each" includes your own deck: every Vampire that lands strips the top card off everyone at the table, hers included, and stacks it beneath a shared pile of collection counters. What separates her from an ordinary impulse-draw trinket is who gets to spend from that pile. Only you may play from it, and only from cards your abilities exiled, with mana of any color. That last clause is the strategic center: the fixing baked into a five-drop means the pile is castable regardless of what colors your opponents run, so a multiplayer game becomes a slow-motion heist where the more decks she taxes, the deeper your toolbox grows. Flash is the reason to hold her: cast her in response to a Vampire spell already on the stack and she is on the battlefield to see that Vampire enter, collecting off her own arrival and the incoming body in one window. The throttle is "once each turn." An exile pile that grows by one card per player per Vampire per turn would bury the table, so the ceiling on spend rate is what stops her from simply out-carding everyone in a handful of turns. She rewards a wide Vampire board not for combat but for library velocity, which is a genuinely unusual axis: the tribe here is a resource pump rather than an attack force, and the 2/5 body sits back and lets the pile do the winning.