Does anyone know where there is an online list of all the vocal harmony settings that this keyboard has ?

What do people think of them ?

They are in the owner's manual, which I'm sure you can download from Yamaha. They may be on PSR Tutorial page also.
I think the settings are quite good. I find myself using only a few for my particular type of playing, but most all of them are good.
I forget the exact names since my keyboard is still in the van (don't worry Gary, it's 70 degree here today), but I use the Girl harmony, Country Men, Mixed Choir, and of course the infamous Karaoke Girl, which they screwed up on the 2000. I also use Squeaky Mouse for novelty on occasion.
There are settings to accomodate Chordal mode, Vocoder Mode, and Song Mode.
You can edit all presets and save to User Memory if necessary.
To get the best sound, it is critical to adjust the mic input settings properly. A little trial and error and you'll love it.
DonM