Ircam Lab The Snail by dBzipper
The Snail is my go-to tuner now. It has all the benefits of a stroboscope tuner, and adds a huge full spectrum display. The fast spectrum is so huge that they wrapped it around in a spiral, overlapping at the octaves, very cleverly. That is where it got the snail name, no doubt. You can see the overtones and the harmonics, all moving simultaneously as you tune it. There are cool-looking moving phase displays that can overlay within the note blobs, but I haven't figured out how to use that yet, but they are fun to watch.
It took about 1/8 of my CPU, but with the large amount of signal processing it is doing, that is to be expected. If you play a chord, it shows each note in the chord. You can see what notes are being played in song files. When used as a tuner, you would de-activate it afterward.
I had to run it through a DAW, Pro Tools, as my guitar is plugged in through a DI into a pre-amp into a MOTU 828x. Sampling at 96 Ksps. There is a standalone version, but it is not yet enabled for ASIO.
There is a rotating hexagon that spins with respect to the phase of your string sound versus the tuning frequency (which automatically adjusts to whatever note you are tuning). You can use that for intonation by making the hexagon rotate (or ideally not move) in the same direction at the same speed for the fretted 12th fret versus the harmonic at that fret. The guitar never sounded better after performing the intonation.
The Snail is really something new, something you probably have never seen before, and is an amazing thing that should be able to help you make your instrument better sounding, and help you figure out what notes are being played on recordings. There is a free trial from IRCAM. I think that you will love it.