Rode VideoMIC Me is worth your consideration. This is a shotgun mic that plugs right into a smartphone’s 3.5mm TRRS headphone jack, letting you record quality audio in the process.
The mic focuses the audio capture on what’s directly in front of the capsule thanks to the directional polar pattern. It’s primarily intended for use with compatible smartphones and devices that sport 3.5mm TRRS connections. The mic comes with a flexible mounting bracket as well as a furry windscreen for achieving a better sound in windy conditions.