I made a guitar tuner app using Flutter and Rust
There are two Drop D tunings listed and one is actually Drop C. There is no Drop D♭, you call it Drop C♯ which while it's technically the same set of tones, it's now how guitar players think of it. You have the same issue with E♭ Standard. Each of your notes in these tunings are listed as sharps instead of flats, which is not how guitar players think of the notes in these tunings.Also, you might want to consider polyphonic tuning. That's what would set you apart from everybody else. I bought a TC Electronic PolyTune earlier this year and it's been a game changer. It's much faster and easier to get tuned