I'm constantly amazed at the new Hidden Mickeys (new for me, at least!) that folks tell me about. Like this one in DinoLand U.S.A. - walk to the rear entrance of Chester & Hester's Dinosaur Treasures shop to find this classic Hidden Mickey, made of dark spots at the lower left of the left side of a "Cold Drinks" dispenser. It's just above the lower red horizontal band. I hope it lasts! (Thanks to Alicia Dakins).
Here's a cool Hidden Mickey image in The Boneyard. Upstairs to the rear left in a fenced-off archeology display, a small full-body Mickey figurine sits on the horizontal bar of a red bicycle. Various plastic dinosaurs perch on other parts of the bicycle. (Thanks to Leah Lakatosh and Stephanie Harrison).
Some Hidden Mickeys are changed over time due to weather or other external effects. This upside-down classic Mickey image seems to been distorted over the years. It's on the back of The Tree of Life - visible from the path between Africa and Asia. To find it, look above the eye of the hippopotamus. What do you think?
As you're exiting the park, stop by the restrooms to your right before the turnstiles. What about these rocks in the wall in front of the restrooms? A Hidden Mickey? (Thanks to DisneyR&N).
Enjoy the hunt!