Recessed Corner: simple and easy to do.
  – fold back to form a triangular flap behind,
  – fold the flap forward again with a slight recess.
Variations include folding the tip of the recessed corner behind (middle), or forward (right).

Squashed Rabbit-Ear Corner: this fold is slightly more complex but looks fabulous.
  – fold the corner forward to form a triangular flap,
  – make a rabbit-ear fold,
  – lift and squash the smaller flap to form a kite shape.
Variations include folding the “kite” in half and flaring the two halves (middle); or fold the entire rabbit-ear back and then turn the page over (right).

Pleated Corner: add pizzaz by pleating the corner in an accordion (fan) manner. You can leave the pleats in a stack (left), or splay them out forming ripples (right).

Wedge-Pleated Corner: similar to above except that the pleats are not parallel to one another. Here, the pleats are folded so they radiate from one point. The wedge-shaped pleats can be stacked (left), relaxed (middle), or splayed out like rays from the sun (right).

Butterfly Corner: If you don’t mind cutting or ripping your corner slightly, then this easy butterfly makes a beautiful corner! To make it,
  – fold the corner of a page forward to form a triangular flap,
  – cut a slit down the middle of the folded triangle,
  – fold the cut edges back to form the lower wings.
Variations include folding wide or narrow wings.