Thanks! I'll look up those other guitar tunings and add them. It's pretty trivial to add new ones--like you guessed, I walk up each string and find the notes of the scale or chord. I forgot to mention this in the original post, but the project is actually open-source [1] (it's on the about page but probably should have noted it). Feel free to submit pull requests or file issues. The code is pretty much create-react-app + typescript.

>Also, the open G is not as I would expect, but I think the DGDGBD tuning is what people expect on guitar.

You mean it's not what you'd expect for dobro, right? I haven't really played guitar in years, but I think that's right for guitar. I'll add a dobro section now, I just need to find the actual octaves for the notes in the tunings you list. Adding new tunings is just a simple-change [2] (though I may need to adjust mobile layout for more than six strings). I can add pedal steel, too. I wanted to add banjo, as well, but need to figure out that fifth string.

[1]: https://github.com/uhoh-itsmaciek/fretboard.cool [2]: https://github.com/uhoh-itsmaciek/fretboard.cool/blob/master...