Metronomes.app's answer
It's free, available in any browser anytime. It save cached version so you can work with it offline.
Metronome M1 - Simple but extremely accurate metronome for mobile.
MyGuitarTuner.com - Online microphone tuner for guitar, ukulele, violin and other instruments. Tune by ear or using the microphone of your device. It's fast and accurate algorithm makes it one of the best online microphone tuners available.
Mobile Metronome - Mobile Metronome is a pretty complete metronome for any usage, from the simplest beat count...
Fine Tuner - Fine Tuner is a minimalistic guitar tuner that utilizes your device's built-in microphone.