PanosFX.com has over 30 free actions and their commercial actions are very affordable. Here are three of my favorites.
The Stickers n Shapes set contains two Photoshop actions:
The Stickers action turns your image into a round sticker, which you can use with your crafting projects. The action has been optimized to work with images with sides at least 950 pixels.
The Clear Tape action turns your image into a Polaroid photo and adds sticky tapes on the top edge. You can even add sticky tapes on each photo corner. In addition the action creates trapped air bubbles under the tape!
The PanosFX Out of Bounds set contains two advanced Photoshop actions that simplify the steps needed to create this impressive and popular effect.
The actions are very flexible; at the beginning you define the border size & perspective; then you define the out-of-bounds areas and add the shadow effects. The actions make use of layer masks that allow you to fine tune the effect at a later stage.
The Paper Cube set lets you use up to 6 photos and then print and create a real paper photo cube.
The first Photoshop action creates a cube that has the same photo printed on each facet. The second action lets you use 6 different photos. The third and the fourth Photoshop actions produce a Christmas paper cube. Hang it from the Christmas tree, use it as a present box, or give it to your kids as a toy!