Illusionist's Bracers

Doubling is the single most explosive thing you can do to an activated ability, and this is the cheapest, most portable way to bolt it onto anything that taps, sacrifices, or pings. The keystone clause is the mana-ability exclusion, and the reason for it is a rules technicality rather than a power ceiling: mana abilities don't use the stack, and this Equipment can only copy abilities that do. Cut those out and what remains is a magnet for creature abilities the game actually cares about doubling: a second tap-to-deal-damage activation, a second token, a second reanimation, a second pump. The "you may choose new targets" line is what turns the copy from redundancy into reach, letting one activation answer two separate problems at once. The economics run double-edged: the copy hits the stack as a free second instance, but the original activation still costs whatever it costs, so the payoff only lands when the ability is cheap relative to its effect. Equipment also means the multiplier sits exposed on a creature that has to survive a turn before it can tap again, and the equip cost is steep enough that redeploying after a removal spell stings. Inert next to a vanilla body, lethal next to a creature whose activated ability was already worth one copy, it asks the deck to bring the engine and supplies only the multiplier.