If you love to hate annoying sounds, or perhaps you get joy out of pranking people then this next app might be something to look into.
Sounds Grate is not only a clever play on words but also a small collection of extremely irritating sounds that can be played on demand. While the functionality is pretty much limited to selecting from 3 different noises (with the ability to purchase more at one dollar each), the app does offer some configurations for the mosquito and violin noises that let you choose the level of irritation that they will bring. The other sound is nails on the chalkboard. These three sounds are available right away for free with 4 other sounds available as in-app purchases. You can also choose to purchase Sounds Grate Gold which includes up to 15 sounds.
Overall, the design of the application is virtually non-existent, there is no support for even basic retina images and the presentation is much below average. However, if you’re looking for something truly annoying, the sounds are worth a look considering the application is free.