BlurFX

BlurFX.  Saves full resolution.  Has three types of blur along with multiple filters and 2 sliders.
Free today.  Get it.

I'm not really sure what the FX means but Apps with FX in their name have several types of filters.  I have several and they're all fun to use.  BlurFX is fun also.  It has 3 types of blur: motion, gaussian and median.  It also has sliders to control the amount of blur and to add vignetting.  The image starts as 100% blurred and you "Brush" off the blur where desired with your finger.  It's a kick and for the creative among us quite a good tool I suspect.