Which rocks will go better (update info & pic added)

[SandyinMonterey]

The stone work you have looks like tan/brown color(s)...warm tones. I'd go with the middle one if you want a more monochromatic look or the far right (darker) for a bit of contrast. I think the ones on the far right are grey? To me, grey is a cool tone. There are stones that come in different shades of browns and tans with some white mixed in. We have those and like it.