Heartstone 
Artifact
$1.89 #3868 0.12 28.6 years
Activated abilities of creatures cost 
less to activate. This effect can't reduce the mana in that cost to less than one mana.
less to activate. This effect can't reduce the mana in that cost to less than one mana.Click a line or tag to filter
Cards similar to Heartstone expected a card that isn't here?
Reports become test cases the matcher is graded against before an update ships. Delvefall isn't a chatbot guessing, it compares the printed rules text of every card with plain math, and examples like yours decide which differences should count.
Training Grounds98%
$5.08↑#1040↑0.53↑16.5 years↓
"Activated abilities of creatures you control cost 
less to activate. This effect can't reduce the mana in that cost to less than one mana."
less to activate. This effect can't reduce the mana in that cost to less than one mana."
Biomancer's Familiar98%
$1.90↑#3061↑0.38↑7.7 years↓
"Activated abilities of creatures you control cost less to activate. This effect can't reduce the mana in that cost to less than one mana."
less to activate. This effect can't reduce the mana in that cost to less than one mana."
Zirda, the Dawnwaker94%
$1.50↓#33490.37↑6.5 years↓
"Abilities you activate that aren't mana abilities cost less to activate. This effect can't reduce the mana in that cost to less than one mana."
less to activate. This effect can't reduce the mana in that cost to less than one mana."
Forensic Gadgeteer91%
$2.04↑#1406↑0.25↑2.7 years↓
"Activated abilities of artifacts you control cost less to activate. This effect can't reduce the mana in that cost to less than one mana."
less to activate. This effect can't reduce the mana in that cost to less than one mana."
Power Artifact88%
$181.90↑#9827↓0.73↑32.6 years↑
"Enchanted artifact's activated abilities cost less to activate. This effect can't reduce the mana in that cost to less than one mana."
less to activate. This effect can't reduce the mana in that cost to less than one mana."
Professor Hojo87%
$0.24↓#5026↓0.121.4 years↓
"The first activated ability you activate during your turn that targets a creature you control costs less to activate."
less to activate."
Convergence of Dominion87%
$0.92↓#12037↓0.124.0 years↓
"As long as you control your commander, activated abilities of cards in your graveyard cost less to activate. This effect can't reduce the mana in that ability's activation cost to less than one mana."
less to activate. This effect can't reduce the mana in that ability's activation cost to less than one mana."
Mutagen Man, Living Ooze86%
$1.73↓#6041↓0.43↑0.6 years↓
"Activated abilities of artifact tokens you control cost less to activate."
less to activate."
Embalmer's Tools85%
$0.19↓#13080↓0.22↑9.5 years↓
"Activated abilities of creature cards in your graveyard cost less to activate."
less to activate."
Agatha of the Vile Cauldron84%
$4.67↑#5662↓0.60↑3.1 years↓
"Activated abilities of creatures you control cost 
less to activate, where X is Agatha's power. This effect can't reduce the mana in that cost to less than one mana."
less to activate, where X is Agatha's power. This effect can't reduce the mana in that cost to less than one mana."
Fluctuator81%
$0.77↓#8422↓0.0528.0 years
"Cycling abilities you activate cost less to activate."
less to activate."
Blossoming Tortoise80%
$4.94↑#33820.27↑3.1 years↓
"Activated abilities of lands you control cost less to activate."
less to activate."
Tezzeret, Betrayer of Flesh76%
$0.52↓#40680.36↑4.7 years↓
"The first activated ability of an artifact you activate each turn costs less to activate."
less to activate."
Magewright's Stone72%
$9.47↑#2958↑0.34↑20.5 years↓
", 
: Untap target creature that has an activated ability with in its cost."
, : Untap target creature that has an activated ability with in its cost."
Sam, Loyal Attendant72%
$0.44↓#6554↓0.41↑3.3 years↓
"Activated abilities of Foods you control cost less to activate."
less to activate."
Hulk, Gamma Goliath72%
$0.19↓#16252↓0.28↑0.3 years↓
"Power-up abilities of other creatures you control cost less to activate."
less to activate."