All kinds of goodies, just like any workshop. Pick up anything loose on the general theory that you'll need it eventually, and you'll be in good shape.
When you enter, you can see a large square can on the left; that's turpentine. Grab it.
On the work tables, you can find a book about batteries, a rolled-up painting, and a jar full of pennies. Again, grab.
Turn to the right to face the large double doors. On a pillar at the right, there's a garden trowel you need; in the corner on the left, there's a fruit picker, just like the one you used to pick loquats in Nancy Drew 17, The Legend of the Crystal Skull. Take, take!
In addition to the things you can take, there are a number of devices that have to stay here but which you'll need eventually. Notice, for example, the broken cotton gin, the film projector, and the scale next to the double doors.