Sources with this icon might be available in the "For You" section of the in-game store. It's random for everyone so we can't know!
Source Name Source Type Rarity Availability
CP Store (2019-09-27) CP Store Rare
CP Store (2019-10) CP Store Common
CP Store (Pre-Season) CP Store Rare
CP Store - Free Reward for Everyone CP Store Rare
CP Store Update (2020-05-15) CP Store Common