Harry Frank posted My 5 Favorite Expressions: Intertial Bounce, Autofade, Snap Zoom In/Out, Y Axis Jitter, toComp. He explained them and made them available as FFX presets for AE CS3:
"I realize that expressions can be daunting, and some would rather copy and past useful code rather than learn the language. That’s cool with me. Therefore, I’d like to share with you my 5 favorite expressions. These are expressions I use in just about every project, and I consider them to be incredible workflow enhancements."