A question of magic the gathering artifacts?

There are 3 different artifacts I've found that fit this criteria:

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-- Jester's Scepter {3}

When Jester's Scepter enters the battlefield, exile the top five cards of target player's library face down. You may look at those cards for as long as they remain exiled.

{2}, Tap, Put a card exiled with Jester's Scepter into its owner's graveyard: Counter target spell if it has the same name as that card.

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-- Null Brooch {4}

{2}, Tap, Discard your hand: Counter target noncreature spell.

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-- Ring of Immortals {5}

{3}, Tap: Counter target instant or Aura spell that targets a permanent you control.

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The source link below shows the search I did on the Gatherer database for artifact cards containing the words "counter", "target" and "spell". There is a fourth card in that search, but it requires sacrificing itself.

Given the costs and restrictions of these artifacts, I think you'd be better off just playing lots of Essence Scatter and Negate. On the other hand, you might try searching for creatures with the ability to counter spells, as there are plenty that don't need to be sacrificed.