If your into retro noise you may like Zx Plectrum. It’s a one trick pony but then again it’s just a buck. I grabbed it and annoyed everyone around me for a good twenty minutes. That alone was worth the dollar.
“Play the ZX Specturm loading sounds as a musical instrument on your iPhone/iPod/iPad! Relive the crisp sounds of your youth! Change the loading phase and pitch to make some weird but familiar sounds!” – davesapien.com
For more info: davesapien.com