Legendary Planeswalker - Vraska Winding Constrictor If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead
13 Claydol (2008) Card 15/106 From Diamond & Pearl: Great Encounters Part of the Diamond & Pearl: Great Encounters set, Claydol is an unassuming card that is surprisingly effective in battle
While just enchanting things for value is a fine, fun way to play Estrid, the Masked, things can get out of control quickly if you start playing cards like Overgrowth and Fertile Ground so that Estrid's +2 acts like a massive ramp spell, and then The Chain Veil (perhaps enchanted with a Mask aura thanks to Estrid's 1) give you an easy way to activate your Estrid, the Masked an infinite number of times, potentially making infinite mana by untapping your lands and eventually winning with her Replenish ultimate
Other cheap cards Im excited to play with: Dragonborn Champion, Hurl Through Hell, Maddening Hex, Netherese Puzzle-Ward, Vengeful Ancestor, Sudden Insight, Deadly Dispute, Flumph, Ingenious Smith, and Meteor Swarm
Instant Color tag templates(None) Reality Shift Exile target creature