There are five types of collectibles to gather in PAW Patrol.
1. Pup Treats: Most Important! These are scattered all over the levels and are also rewarded from beating minigames. They are the main collectible in the game and there are 7250 total. You cannot unlock all the other collectibles until you have all 7250/7250. You must gather all from every level as well as all from every level of every minigame to gather every one.
2. Badges: Every main mission has 3 hidden badges to collect and each badge represents either a character or animal collectible and thus all 3 badges need to be collected on all main missions to gather all collectibles.
3. Character: These will be the last you unlock once you get all the pup treats. They are unlocked by getting all 3 badges on every story mission and by gathering all pup treats.
4. Location: These are gathered from playing on every location. You must play every main mission and any of the minigames that are not set in the same location as the main missions to collect all of these. According to AthleticMist, the last only unlocks at 4,500 pup treats.
5. Animal: These are gathered by collecting all 3 badges in every story mission. There are only a few and this will be the first collectible achievement you unlock. According to AthleticMist, the last only unlocks at 4,200 pup treats.
It should be noted that there is an achievement for gathering all badges and all pup treats on a level for each level in the game. These will all come naturally when trying to go for this achievement.