Umori, the Collector 
Legendary Creature — Ooze
$0.29 #10862 0.29 6.4 years
Companion — Each nonland card in your starting deck shares a card type. (If this card is your chosen companion, you may put it into your hand from outside the game for 
as a sorcery.)
as a sorcery.)As Umori enters, choose a card type.
Spells you cast of the chosen type cost 
less to cast.
less to cast.Click a line or tag to filter
Cards similar to Umori, the Collector 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.
Stone Calendar84%
$14.67↑#20270↓0.48↑32.1 years↑
"Spells you cast cost less to cast."
less to cast."
Zirda, the Dawnwaker77%
$1.88↑#3308↑0.49↑6.4 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."+1 more matching line
Helm of Awakening76%
$1.51↑#1903↑0.3629.6 years↑
"Spells cost less to cast."
less to cast."
Spellwild Ouphe74%
$0.32↑#16327↓0.2919.3 years↑
"Spells that target this creature cost less to cast."
less to cast."
Killian, Ink Duelist73%
$0.29#3392↑0.39↑5.4 years
"Spells you cast that target a creature cost less to cast."
less to cast."
Memory Crystal72%
$2.14↑#23969↓0.60↑28.2 years↑
"Buyback costs cost less."
less."
Semblance Anvil71%
$3.63↑#2114↑0.2915.9 years↑
"Spells you cast that share a card type with the exiled card cost less to cast."
less to cast."
The Immortal Sun70%
$11.74↑#2602↑0.73↑8.6 years↑
"Spells you cast cost less to cast."
less to cast."
Lutri, the Spellchaser70%
$0.48↑#122370.00↓6.4 years
"Companion — Each nonland card in your starting deck has a different name."