As long as were milling ourselves, the number of Spirits will incrementally increase as we loop, and at some point, we can start hitting an opposing library for three cards while still making our Spirit allies
Some cards came in sets and if one of those cards were missing, you could no longer use the data stored on them
It has a great lifegain use for your extra mana each turn (most likely an opponent's turn)
Acolyte of Affliction Atlas, Sizable Stooge Baba Lysaga, Night Witch Beifong's Bounty Hunters Brako, Heartless Hunter Carth the Lion Chevill, Bane of Monsters Cleopatra, Exiled Pharaoh Dai Li Agents Earth Village Ruffians Greta, Sweettooth Scourge Grim Flayer Hapatra, Vizier of Poisons Honest Rutstein Killmonger, Scourge of Wakanda Kraven the Hunter Long Feng, Grand Secretariat Meren of Clan Nel Toth Michonne, Ruthless Survivor Old Rutstein Putrid Pals Reyhan, Last of the Abzan Savvy Hunter Shessra, Death's Whisper Skull Prophet Stalwart Successor The Most Dangerous Gamer The Serpent Society Titania, Rugged Rumbler Vhati il-Dal Winter, Cynical Opportunist Witherbloom Apprentice
Every now and then someone will have Kataki, War's Wage, so keep that in mind if you can afford to play around it
However, it is vulnerable to disruption cards like Sabrina and chip damage dealers such as Darkrai EX and Greninja