Fishlegs' Dragon Cards

Fishlegs's Dragon Cards are like the Dragon eye Lenses, as they tell him and his friends about the "new" unknown dragons they're come across; he keeps them in the pouch on his belt. They each have an image of a dragon, along with their class, size, speed, abilities, strengths and other important information.

Race to the Edge season 2
In Crash Course, when the Riders came across the Cavern Crasher, Fishlegs got the cards out of his pouch to identify the dragon. Fishlegs clamed that he had been working on them for months, before telling them how they work.

How to Train Your Dragon 2
After Eret brought Astrid and the other Riders to Drago's location, they saw a group of ships around a "pool" of bubbles. Fishlegs got his out to see if those bubbles were made by dragon and what kind it is, he had trouble finding "the" card that can tell him what dragon it is and when Drago's Men "found" them, Fishlegs dropped the cards in his hands when he put his arms up.

Trivia

 * The cards appears in the game Dragons: Rise of Berk as a collectable in completing collections.