Soundhound is God awful for finding stuff by humming. I had a song stuck in my head for years. Probably over 20ish years. I just kept whistling and humming but never knew the artist or the words. Google gave it to me first shot. I swear by Google for the humming technique.

Pros: Can immediately suggest an alternate idea that was otherwise unexpected or could not be spurred by creative means. It gives invaluable help when dealing with writer's block.

Cons: When relied upon solely or in great amounts, can easily make the writer dependent, predictable and lazy in the creative process.