These count not only the traditional watermarks found in a card's text box, but also the faction marks found in the bottom right corner of Contraptions
Instantaneous effect (in a game where almost everything is a Charged Attack, and enemies can dodge those attacks by simply taking their turn and walking away), 4 tile range if you're a Chemist or have the Throw Item support skill equipped, invariable 100% chance of success as long as there's a clear line of sight, useful until the endgame, and doesn't vary in effectiveness based on the target's Faith
Merfolk are nostalgic, unique, and even powerful, with the right commander at the helm
Sylvan Library The original Search for Azcanta
This leads to lower confidence in the card, and thus lower prices