Stickers
From Poliwager Wiki
Stickers are a collectable on Poliwager Adoptables representing all available Pokémon on the site. They are exclusively found by fishing in Politoed Pond. Just like Pokémon Eggs the type of Sticker you find is determined by the Pokémon's rarity and what season they are available in. Collecting Stickers can help you unlock better rods for fishing otherwise its just for fun. You can see what Stickers you have collected by going to your Pokédex and selecting Stickers under "Registered Status." A Pokémon's Pokédex page will show how many Stickers of that Pokémon have been found and how many of them you've obtained, including the first and last time you've obtained it.