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.