Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
Tuner Eclipse - A simple and accurate guitar tuner for iOS
Geary - Geary is an email application built for GNOME 3.
Roadie Tuner - Fine tune your guitar in seconds
Airmail - Airmail is a lightweight and lightning fast mail client for Mac.
Guitar-Tuner.org - Guitar Tuner | Online Tuning | Guitar-Tuner.org