I have never loved accent tiles in showers, but, if you can't match the existing tile, that might be a reasonable, somewhat obvious, solution. Can at least one tile be salvaged above or below the shower head to replace the one on the left? Then a decorative coordinating mosaic strip installed from floor to ceiling.

Natural tiles are all slightly different and you only need a few. Have you purchased new tiles and brought them home to try? They might not be as obvious as you think after installation.

I'd rather see a difference than look at accent tiles. Never a fan either.

I was going to say that you might steal some tiles from a closet floor but the risk of breaking them would be high.

Sorry but really if there water leaking anywhere you should rip it all out and start again

Rip out the tile from the wall with the damage and replace the whole area with pebble mosaic from Island Stone. French Tan Perfect Pebble would probably match well.

Man, what a bummer! I agree with flopsycat1. Add a strip of new tile all the way from floor to ceiling and maybe make a cubby in the other low hole that is off to the side. Can't tell how low it is, I have put in many leg shaving shelves, this could be a soap, foot hold for shaving legs.....

Can you find the same tile in the smaller size (4x4) that you have used elsewhere? If so, I would go with the previous suggestions of making a vertical accent strip behind the showerhead/handle, but you could tile it with the same tile just in a different size. Hopefully the same size that matches what you have used elsewhere. It will make the "accent" less obvious.

Did this get resolved?

Not for me. There are no replacement tiles. A few tiles in the shower are broken or have a old time repairable shower rod ceramic tile holder broken and two others relating to nothing.