Is it black & white? Or is it color? This leaves a wisp of color, just a hint, for a unique vintage look.
Just a little snap and contrast without affecting color tone or saturation. If you want to boost and add vibrance to colors too, try Boosterizer.
A very rich, subtly warm, black & white look that has snap and contrast. The toning is only in the shadows, maintaining clean highlight areas.
The subtle color palette of your favorite films. Do you remember film?
Here's a soft, diffused effect - like sun scattered its light on your image. Use when the sun should come from top left in the image.