ImpedeUU
Instant
Choose one —
• Counter target instant or sorcery spell
• Counter target activated or triggered ability
With the same cost, another version is to replace "instant or sorcery" with "artifact or enchantment".
Try AgainUU
Instant
Counter target spell if it isn’t the first spell cast this turn.
UnderestimationUU
Instant
Counter target spell, activated or triggered ability unless its controller pays 2.
Weight of ManaUU
Instant
Counter target spell unless its controller pays X, where X is the highest converted mana cost among permanents they control.
Star Exile1WU
Instant
Choose one —
• Counter target legendary spell
• Exile target legendary permanent
Hindered PlansWU
Instant
Counter target spell unless its controller pays 3. If that player does, you gain 3 life and draw a card.
Evaporate SpellRGUU
Instant
Counter target spell, triggered or activated ability. Add 2 mana in any combination of colors.
Erase Mind3BU
Instant
Counter target spell. Its controller reveals their hand and discards all cards that share a type with that spell.
CountermindBU
Instant
Counter target spell unless its controller discards a card with an equal or higher converted mana cost.
CountermagicWU
Instant
Counter target noncreature spell. You gain 3 life.
CounterbloodBU
Instant
Counter target spell unless its controller sacrifices a nonland permanent.
Cycling 2 (2, Discard this card: Draw a card.)
Artificer's UndoingU
Instant
Choose one —
• Counter target artifact or enchantment spell
• Return target artifact or enchantment to its owner’s hand
Mana Fertilizer1GUU
Instant
Counter target spell. You may put a land card from your hand onto the battlefield.
Underestimation, probably too much. A tax of 2 is significant enough that it will work most of the early game and it hits such a wide range of targets that its rarely useless.
Weight of Mana, this would feel better if it was the CMC you control rather than they. Gives a harder requirement and better consistency.
Hindered Plans, this is a strange one it feels too strong at its current cost but not so much as to warrant a higher cost.
Evaporate Spell, an interesting fusion of Voidslime and Plasm Capture. Being 4 colors it could probably refund the whole cost, it will be hard to gain actual value off of it because you can't reduce its cost and your not untapping lands.
Counterblood, due to the nonland disclaimer this is probably strong enough without cycling.
Mana Fertilizer, this is too expensive for the effect. At this cost I would expect to staple Rampant Growth on Counterspell. For its current effect GUU is sufficient.
Counterblood. I thought that it could be useless when the opponent has nothing to sacrifice or has tokens. It can hit enchantmens, but it's not your choice anyways.
Hindered Plans. Life gain or the mana tax can be lowered to 2.
More counterspells:
Missing TargetUU
Instant
Counter target spell that doesn't have one or more targets.
It can counter anything, but removal and deal damage.
Essence Leak1U
Instant
Counter target spell if its controller's life total has changed this turn. (life gain and life loss cause life total to change)
Instant
Choose one —
• Counter target instant or sorcery spell
• Counter target activated or triggered ability
With the same cost, another version is to replace "instant or sorcery" with "artifact or enchantment".
Try Again UU
Instant
Counter target spell if it isn’t the first spell cast this turn.
Underestimation UU
Instant
Counter target spell, activated or triggered ability unless its controller pays 2.
Weight of Mana UU
Instant
Counter target spell unless its controller pays X, where X is the highest converted mana cost among permanents they control.
Star Exile 1WU
Instant
Choose one —
• Counter target legendary spell
• Exile target legendary permanent
Hindered Plans WU
Instant
Counter target spell unless its controller pays 3. If that player does, you gain 3 life and draw a card.
Evaporate Spell RGUU
Instant
Counter target spell, triggered or activated ability. Add 2 mana in any combination of colors.
Erase Mind 3BU
Instant
Counter target spell. Its controller reveals their hand and discards all cards that share a type with that spell.
Countermind BU
Instant
Counter target spell unless its controller discards a card with an equal or higher converted mana cost.
Countermagic WU
Instant
Counter target noncreature spell. You gain 3 life.
Counterblood BU
Instant
Counter target spell unless its controller sacrifices a nonland permanent.
Cycling 2 (2, Discard this card: Draw a card.)
Artificer's Undoing U
Instant
Choose one —
• Counter target artifact or enchantment spell
• Return target artifact or enchantment to its owner’s hand
Mana Fertilizer 1GUU
Instant
Counter target spell. You may put a land card from your hand onto the battlefield.
Weight of Mana, this would feel better if it was the CMC you control rather than they. Gives a harder requirement and better consistency.
Hindered Plans, this is a strange one it feels too strong at its current cost but not so much as to warrant a higher cost.
Evaporate Spell, an interesting fusion of Voidslime and Plasm Capture. Being 4 colors it could probably refund the whole cost, it will be hard to gain actual value off of it because you can't reduce its cost and your not untapping lands.
Counterblood, due to the nonland disclaimer this is probably strong enough without cycling.
Mana Fertilizer, this is too expensive for the effect. At this cost I would expect to staple Rampant Growth on Counterspell. For its current effect GUU is sufficient.
Hindered Plans. Life gain or the mana tax can be lowered to 2.
More counterspells:
Missing Target UU
Instant
Counter target spell that doesn't have one or more targets.
It can counter anything, but removal and deal damage.
Essence Leak 1U
Instant
Counter target spell if its controller's life total has changed this turn. (life gain and life loss cause life total to change)