IMO The square and rectangle looks the same amd the lower looks way lighter for your patio. I would go with the first two, which the square one would be my first option.

Are most of the pieces of silver travertine like the top two - or like the beige piece on the bottom left?

I like how the slate looks between the top left piece and the long piece on the side. The beige looks fine next to the bottom left piece - but I don't think it would look great if the sample of it was between the top piece on the left and the long piece on the right.

However, if more pieces look like the beige piece on the bottom left, the slate may be too dark . . .

Thank you for your comments. Most of the pavers are gray like the top 2 pieces. I called a local stone yard and they say they have more color options so I am going to look tomorrow. Ideally I think I want a medium gray?

I would not choose such a busy stone at all

Medium gray sounds fine, it’s a personal choice.

Depending on how often you power wash the stone, you will need to brush in/wet down new polymeric sand periodically. Make a note of the color you choose now for the future plus you will have a chance to change a bit the color down the road.

I just power washed and refilled my dry set bluestone patios and they look like new. It’s an easy level DIY.

If that is the actual picture of your patio, then call me crazy , but I like the dark line that you see. It shows the layout of the blocks and doesn't look as thick as the sample you showed.

I have to agree with Debbi because of the variation in tone and color of your stone. A grey will blend with some and create a boundary with others. Dark will work the same with everything as a narrow outline.

Sure hope this is in a non freezing climate with that porous holey stone.