The ST-300 strobe tuner guitar pedal from Sonic Research has five programmable presets for alternate tunings and a USB port for customizing settings via a text file in the ST-300 Editor desktop application.
This separate, unofficial web app improves the settings editing experience with controls for number of strings, note and octave, cent offsets, A4 reference pitch, and transpose semitones with range limits for each based on the manual.
A settings text file can be imported and exported so it can then be opened in the official ST-300 Editor application and uploaded to the tuner.