Psychonauts 2

At any point after unlocking the Quarry, head to Otto's Lab and ask him if he has any devices to lend out. He will give you a Psi-Enhanced Camera and a Thought Tuner. As soon as you leave Otto's Lab, equip the Thought Tuner and you should find a Stray Thought in the parking lot.

The Thought Tuner is given to you temporarily by Otto Mentalis from his workshop. By loaning it to you, you can use it to access stray thoughts that may be found throughout the open hub worlds. One stray thought in particular to consider would be just outside Otto's workshop, or two within the Atrium of the Motherlobe to get those pesky PSI Cards that hang just out of your reach. There is also one in the Questionable Area in the playground, and two more near Morris's treehouse and Lili's garden spot. Finally, there is one within the Green Needle Gulch area near Ford's old treehouse, but located above it. It's a little game of hot-and-cold until you are standing right upon the thoughts, which release them to be used with Mental Connection.