Stone Calendar 
Artifact
$14.67 #20270 0.48 32.1 years
Spells you cast cost 
less to cast.
less to cast.Click a line or tag to filter
Cards similar to Stone Calendar 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.
Helm of Awakening94%
$1.51↓#1903↑0.36↓29.6 years↓
"Spells cost less to cast."
less to cast."
Spellwild Ouphe90%
$0.32↓#163270.29↓19.3 years↓
"Spells that target this creature cost 
less to cast."
less to cast."
Memory Crystal89%
$2.14↓#239690.60↑28.2 years↓
"Buyback costs cost less."
less."
Pearl Medallion86%
$5.55↓#454↑0.23↓28.9 years↓
"White spells you cast cost less to cast."
less to cast."
Killian, Ink Duelist85%
$0.29↓#3392↑0.395.4 years↓
"Spells you cast that target a creature cost less to cast."
less to cast."
Sapphire Medallion85%
$7.39↓#365↑0.30↓28.9 years↓
"Blue spells you cast cost less to cast."
less to cast."
Umori, the Collector84%
$0.29↓#10862↑0.29↓6.4 years↓
"Spells you cast of the chosen type cost less to cast."
less to cast."
Uthros Psionicist84%
$0.31↓#9825↑0.23↓1.1 years↓
"The second spell you cast each turn costs less to cast."
less to cast."
Raging Battle Mouse84%
$0.24↓#12241↑0.06↓3.0 years↓
"The second spell you cast each turn costs less to cast."
less to cast."
The Immortal Sun84%
$11.74↓#2602↑0.73↑8.6 years↓
"Spells you cast cost less to cast."
less to cast."
Naiad of Hidden Coves84%
$0.22↓#10368↑0.526.6 years↓
"During turns other than yours, spells you cast cost less to cast."
less to cast."
Highspire Bell-Ringer84%
$0.17↓#10995↑0.17↓1.4 years↓
"The second spell you cast each turn costs less to cast."
less to cast."
Emerald Medallion84%
$4.07↓#586↑0.20↓28.9 years↓
"Green spells you cast cost less to cast."
less to cast."
Geyser Drake83%
$0.15↓#8498↑0.432.4 years↓
"During turns other than yours, spells you cast cost less to cast."
less to cast."
Hardened Berserker83%
$0.03↓#240460.06↓11.4 years↓
"Whenever this creature attacks, the next spell you cast this turn costs less to cast."
less to cast."
Ruby Medallion82%
$13.06↓#291↑0.28↓28.9 years↓
"Red spells you cast cost less to cast."
less to cast."
Racers' Scoreboard80%
$0.30↓#6563↑0.07↓1.6 years↓
"Max speed — Spells you cast cost less to cast."
less to cast."
Jet Medallion80%
$12.06↓#278↑0.22↓28.9 years↓
"Black spells you cast cost less to cast."
less to cast."
Urza's Filter80%
$4.79↓#14485↑0.35↓25.9 years↓
"Multicolored spells cost less to cast."
less to cast."
Council of the Absolute80%
$0.36↓#241330.63↑13.3 years↓
"Spells with the chosen name you cast cost less to cast."
less to cast."