Psychonauts

There are a total of 100 ranks in the game that are earned from obtaining collectibles. The secret 101st rank is tied to completing the "Punching Mini-Game" in Coach Oleander's mind (for more information on this, refer to I LOVE PUNCHING!). Here are a list of all of the collectibles that you must obtain in order to earn this trophy:

• Figments: The most difficult of the collectibles to collect, figments are floating transparent images that are found within the various "mental" worlds in Psychonauts. In all mental levels there are over 50 of them to be found: the least being 60 in one area, with the maximum being over 200 in one level alone. Due to how transparent they are and the fact that some move and pass through walls: finding them all can be a challenge.
   
• Psi Markers: Psi Markers are 9 Psi Cards and a Psi Core put together, granting you one full rank up. These are only found in the real world, with very few in comparison to the rest of the collectibles.
   
• Psi Cards: Psi Cards are floating cards that you can find in both the real world and mental world. When you collect 9 Psi Cards you must buy a Psi Core at the Camp Store (main lodge) then use Cruller's machine located at the very bottom of his lair to turn them into a Psi Marker, thus granting you a rank up.
   
• Mental Cobwebs: Mental Cobwebs are only found in the mental world, they are purple cobwebs usually stuck to walls or in doorways. In order to sweep them away you must purchase a "Cobweb Duster" at the Camp Store for 800 arrowheads. Once you purchase it, use the duster to clean the cobwebs away. Doing so will allow you to exchange the cobwebs for Psi Cards at the bottom of Cruller's lair.
   
• Scavenger Hunt Items: Early in the game you are given a scavenger hunt list that has sixteen items on it, all of the items can be found in the real world. Once you complete half of the list, you will receive four rank ups: after completing the entire list you receive another four rank ups and They Call Me the Hunter.

Do note that at any time you can check the progress of your collectibles within that respective area by going to the pause menu and scrolling right. Scroll right again to see your collectible progress relative to all of the collectibles (if a mental level has more than one area, then that area will also have another set of collectibles).

To assist you in finding all of the collectibles, here is a comprehensive guide that will guide you through the location of all the collectibles in the game (credit to Justinsl1986 for the guide): LINK