Instead of matching your shower floor tile to your other tile maybe you should consider matching your shower floor to your granite. We used the same granite as our countertop for our shower base. It's an option that may be a little pricier but it has definite advantages. There are no grout lines, no mold or mildew, it is guaranteed (at least ours is) not to leak, it has a low threshold, and installation is faster. Ask your fabricator if he does stone shower pans/basins. The link below is for the company we used but I am posting it just or basic information. You can see most of our stone shower pan in the picture below: Here is a link that might be useful: Stone shower pans

Some ideas: Never sure if they are good ideas, but here are some ideas. :-) all the tiles are accessible. https://www.tileshop.com/products/carrara-gris-porcelain-gloss-delray-mosaic-tile-615873?g2=room&c=shower&sc= https://www.tileshop.com/products/hex-matte-white-w-black-flower-porcelain-wall-and-floor-tile-667753?g2=room&c=shower&sc= https://www.daltile.com/product/Coastal-Keystones?shape=Block%20Random&color=Island-Harvest https://www.daltile.com/product/Keystones?color=Arcticwht/Black&shape=Penny%20Rounds And this one is a great use of penny tile: https://www.daltile.com/inspiration-gallery?Cat=Bathroom scroll to the second and third ones

Are those metallic elements really approved for use in a shower? I anticipate green streaks to follow. 0.o Love the overall look here. If those tiles are really wet-approved, then I guess you have two main choices for the floor. 1) a marble-look porcelain tile with not too much veining. seems like it would harmonize here. 2) simple white or light gray tiles that don't really compete with the other elements here. I'd lean light gray, as I think it would make the white parts feel even whiter, and there are some tiles that are very light "concrete" looks that would have a midcentury feel that would fit perfectly. plus, gray is better upkeep (less discoloration over time) than white, especially the grout. Gonna be a great-looking bath!

There must be two billion showers with white subway tile in the shower. What is the vanity. What feel do you want in the space? What are the near bedroom colors? .......and there are more than a billion porcelain tiles in every color one can imagine. Many of which have a matching mosaic for a shower floor. You need to be a participant in the design of your own space before anyone can really advise. : ))