Fist of Suns 
Artifact
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.
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.
Leyline of Mutation 100%
$0.37#6350
"You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast."
Jodah, Archmage Eternal 100%
$0.90#5535
"You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast."
Bringer of the Green Dawn 99%
$1.44#20902
"You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost."
Bringer of the White Dawn 99%
$1.64#20358
"You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost."
Bringer of the Black Dawn 99%
$1.60#14528
"You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost."
Bringer of the Blue Dawn 99%
$4.76#16741
"You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost."