Yes, there are several known beneficial effects of mutation. Not all mutations are harmful or lethal. Mutations occur when a DNA sequence is altered or damaged in such a way that it alters the genetic message carried by that gene. While some may have detrimental results, there are several that are advantageous to the organism.
These are some of the more notable beneficial effects of mutation:
An example of beneficial mutations can be seen in giraffes. Mutations helped giraffes develop long necks, which allowed them to reach tender leaves atop taller trees, increasing their chances of survival as compared to short-necked giraffes in the same population. The mutated genes for longer necks were passed on to the successive generations and in time this feature became more common through natural selection.