Ballynock Cohort 

Creature — Kithkin Soldier
First strike
This creature gets +1/+1 as long as you control another white creature.
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.
Minotaur Tactician 87%
$0.05#31558
"This creature gets +1/+1 as long as you control a white creature."
Ashenmoor Cohort 82%
$0.10#30929
"This creature gets +1/+1 as long as you control another black creature."
Briarberry Cohort 80%
$0.13#25686
"This creature gets +1/+1 as long as you control another blue creature."