Urza's Filter 
Artifact
$4.79 #14485 0.35 25.9 years
Multicolored spells cost 
less to cast.
less to cast.Click a line or tag to filter
Cards similar to Urza's Filter 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 Awakening84%
$1.51↓#1903↑0.3629.6 years↑
"Spells cost 
less to cast."
less to cast."
Stone Calendar80%
$14.67↑#20270↓0.48↑32.1 years↑
"Spells you cast cost less to cast."
less to cast."
Seal of the Guildpact76%
$0.37↓#123750.2910.8 years↓
"Each spell you cast costs less to cast for each of the chosen colors it is."
less to cast for each of the chosen colors it is."
Memory Crystal76%
$2.14↓#23969↓0.60↑28.2 years↑
"Buyback costs cost less."
less."
Herald of Kozilek74%
$0.37↓#6236↑0.07↓10.9 years↓
"Colorless spells you cast cost less to cast."
less to cast."
Pearl Medallion74%
$5.55↑#454↑0.23↓28.9 years↑
"White spells you cast cost less to cast."
less to cast."
Sapphire Medallion72%
$7.39↑#365↑0.3028.9 years↑
"Blue spells you cast cost less to cast."
less to cast."
Ruby Medallion72%
$13.06↑#291↑0.2828.9 years↑
"Red spells you cast cost less to cast."
less to cast."
Uthros Psionicist71%
$0.31↓#9825↑0.23↓1.1 years↓
"The second spell you cast each turn costs less to cast."
less to cast."
Raging Battle Mouse71%
$0.24↓#122410.06↓3.0 years↓
"The second spell you cast each turn costs less to cast."
less to cast."
Naiad of Hidden Coves70%
$0.22↓#10368↑0.52↑6.6 years↓
"During turns other than yours, spells you cast cost less to cast."
less to cast."
Highspire Bell-Ringer70%
$0.17↓#10995↑0.17↓1.4 years↓
"The second spell you cast each turn costs less to cast."
less to cast."
Thornscape Familiar70%
$0.26↓#17790↓0.07↓25.6 years
"Red spells and white spells you cast cost less to cast."
less to cast."
Geyser Drake70%
$0.15↓#8498↑0.432.4 years↓
"During turns other than yours, spells you cast cost less to cast."
less to cast."
Emerald Medallion70%
$4.07↓#586↑0.20↓28.9 years↑
"Green spells you cast cost less to cast."
less to cast."
Jet Medallion70%
$12.06↑#278↑0.22↓28.9 years↑
"Black spells you cast cost less to cast."
less to cast."
Maze Behemoth70%
$0.07↓#24576↓0.10↓13.3 years↓
"Multicolored creatures you control have trample."