SacrificeSaffi Eriksdotter: When target creature is put into your graveyard this turn, return that card to the battlefield.
Saffi is a 2-mana value/combo engine: she protects a key creature from removal or board wipes (sac her to recur it when it dies), then assembles an infinite loop with a recursion creature and a sacrifice outlet to drain the table. Early turns ramp and develop a GW creature base; mid-game you bait removal, accrue value with death/ETB triggers, and eventually go off with Saffi at the center.
Only 2 mana, so she's available early and recurs cheaply after combos
Doubles as combo piece, removal insurance, and a board-wipe hedge
Enables compact, two-card-plus-outlet infinite loops that close games out of nowhere
GW gives strong creature ramp, recursion, and tutors to find pieces
Ability is single-use and only works if the creature actually dies this turn — exile, bounce, and -X/-X dodge it