Tile?

Small, matte tiles are best, because the additional grout lines and matte surfaces provide more friction (less chance of slip and fall). You'll need tile specifically designed for floor use, as many wall tiles lack sufficient friction. Look for a hard wearing tile designed for use in a commercial setting, if you're seeking longevity

( less likely to crack). Always purchase more than you might think you need. Use a very good epoxy grout to avoid cleaning grout lines.

Marble is not a good choice for floors, because it's too slippery. It's also a very poor choice in hard water areas. Stone and rock look nice, but can be difficult for some people to tolerate. If your bath is very large, you might prefer a different color than white. Otherwise, you can use two or more colors, having a border or other design.

You can do any kind of tile you like. That's a classic tile and lends itself to lots of looks. I have 4x4 plain while on the wall and tub and I've chosen classic mosaics for my cottage bathroom. But I looked at everything from wood tile looks to marble looks and they all would've been perfect. I wrote about it if you'd like to see. https://www.exquisitelyunremarkable.com/2019/06/choosing-bathroom-floor.html

Go to Floor and Decor, Home Depot, Lowes or Menards and look at their tile. I chose a porcelain tile for my floor because it is easier to keep clean than ceramic. There are so many different choices and patterns. I have 12 x 18 tiles with a marble look.

Keep in mind that cheaper priced tiles are usually thinner, more brittle, and not as heavy as more expensive choices. This results in more breakage when cutting during the installation stage, which creates a bigger pile of broken tiles that cannot be used. Therefore, cheaper price at the beginning doesn't always mean more $ savings overall.

Thicker floor tiles will also be less resistant to cracking due to weight transferring once they are in place on the floor.

Something else to consider is the sq ft of your floor, and how level it is. It is harder and more work to cut larger tiles to fit into smaller areas such as corners and around jogs in walls.

Absolutely any tile! You've got a great neutral wall tile to work with! You could pick a trendy pattern, wood look, marble, or keep it modern with something simple without pattern.