Nothing with veins or pattern, since your counter has a great deal of movement. I'd look for something in a simple shape, either subway or square, in a pale color. Maybe a bit of crackle or speckle if you don't want a flat/solid color, but I'd definitely not do anything marble or marble look. Colors are tough on monitors, but maybe a pale mushroom would work (or that might be too similar to what you have?) or a soft sage? Hard to tell on my monitor. Get some samples and view them with your counters and cabinets in different lights. Also, if your light bulbs are warm, that will make everything look more yellow. Sage example: mushroom:

Great Ideas, thank you for the input! Since the whole house is 110% wood lol, we were trying to move away from wood in general but some of those do look nice. Beth, the bead type panels would probably work but wood is $$ right now and the cedar planks are about $60 a pop so I wouldn't be able to match that. While the all-white looks great I still think the wood surfaces need to be broken up. That wall is the only wall that isn't wood. For background, I painted the knotty pine tongue and groove walls white ("butter creme" or somesuch). Same with the rough-cut knotty cedar plank wall. Originally, the whole interior looked like the ceiling still does. So, we were really trying to liven the place up with a different material without getting too modern. But of course, sometimes you embrace what you've got. We will be installing shelving where we can on that wall, including some creative (out of necessity) shelving in that corner with the beam. I will make the shelves. Likely out of wood reclaimed from elsewhere in the house. I am framing the interior sill of the window with refinished planks from flooring I pulled up. There will be a hood* above the range (TBD) so that will break up the big wall but also potentially make it a bit crowded in the corner. We really need the shelf space though, as having only lower cabinets really limits storage. I like the look of the unpainted tin but was afraid it would be too overwhelming and/or too contrasting but I will think on that some more. When we were thinking about just painting, we dabbled with something bolder, e.g. blue or sage green on the wall too since our cabinets are kind of utilitarian grey so I guess that is still on the table if we go with some kind of wallpaper or other material. I just don't know how level and finished the wall needs to be in order to take to some of those. The peel-n-stick stuff I have seen is actually quite expensive for a large area and it gets poor reviews. Likely installer error, but still. And because I had to remove the old cabinets and wallpaper due to water damage, mouse infestation, and mold, I ended up jumping the gun and cleaned and kilz primed the whole wall so there is a school of thought that says that mud won't adhere correctly now. *We are debating basic stainless hood or just buying the guts of a hood and building a custom enclosure out of reclaimed wood, painted white to match. I like the subway tile look. Really most tile. But I am pretty exhausted and just don't know if I want to learn tile right now. Ha. I will look into the removable wallpaper. Again, not sure what condition the wall must be in to acquire a good bond and look.

Not sure what it was supposed to look like, but it looks lovely to me. Agreed that I might have chosen a different grout color, but I assume (?) that decision was yours or a designer's and not the contractor's. It is hard to cut small tile pieces in general, glass or otherwise, but the only issues I see here have to do with spacing and alignment (and what looks like grout where the tile meets the counter, where it should be caulked), which probably are more about the tile than the cuts.

I don’t know that I agree with no tile BS at all. Behind the cooktop I’d want something. I wonder if there’s a smaller size of the subway so that 2 full tiles would fit under each window? I think BS along that back wall for sure, up to window sills, behind stove up to hood. Can’t see how the right side ends but if open, no L counter as on left, then there’s a choice on whether to continue tile around on left side. Looking at how plug in plate is placed horizontally under window. I did that with all of my perimeter plug in plates because I have subway tiles. I wanted the plates to fit into a row of tiles & not stand out as they would placed in the usual vertical & higher spot. I had mine lowered to one tile above counter. Lovely as they don’t stand out & catch the eye. Maybe there’s still time to move your remaining wall plates along the wall down & into horizontal?