Ghostly Pilferer 

Creature — Spirit Rogue
Whenever this creature becomes untapped, you may pay {2}. If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: This creature can't be blocked this turn.
click a line to search just that ability, click more to combine them
Cards that do something similar 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.
Hermit of the Natterknolls // Lone Wolf of the Natterknolls 92%
$0.29#11973
"Whenever an opponent casts a spell during your turn, draw a card."
Mangara, the Diplomat 91%
$0.25#616
"Whenever an opponent casts their second spell each turn, draw a card."
Kraum, Ludevic's Opus 91%
#6811
"Whenever an opponent casts their second spell each turn, draw a card."
Cephalid Inkshrouder 91%
$0.35#15443
"Discard a card: This creature gains shroud until end of turn and can't be blocked this turn."
Rhystic Study 90%
$70.26#44
"Whenever an opponent casts a spell, you may draw a card unless that player pays {1}."
Wavebreak Hippocamp 88%
$0.83#2329
"Whenever you cast your first spell during each opponent's turn, draw a card."
Esper Sentinel 86%
$56.22#76
"Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is this creature's power."
Aerial Extortionist 86%
$4.47#2658
"Whenever another player casts a spell from anywhere other than their hand, draw a card."
Mystic Remora 84%
$12.46#98
"Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}."
Chainer, Nightmare Adept 83%
$0.80#1583
"Discard a card: You may cast a creature spell from your graveyard this turn. Activate only once each turn."
Vega, the Watcher 82%
$0.32#2738
"Whenever you cast a spell from anywhere other than your hand, draw a card."
Faerie Mastermind 82%
$10.74#317
"Whenever an opponent draws their second card each turn, you draw a card."
Resilient Wanderer 81%
$0.15#30389
"Discard a card: This creature gains protection from the color of your choice until end of turn."
Volrath's Shapeshifter 81%
#23164
"As long as the top card of your graveyard is a creature card, this creature has the full text of that card and has the text "{2}: Discard a card.""