Just a thought, add a plain mirror and frame it to match the window trim. I would run the whole length from the window to the edge of the vanity.

Something not rectangular. And are you considering a window treatment of some kind?

I agree with RedRyder that square and rectangular aren’t the best choices here. Maybe a funky geometric shape or oval or round.

The Houzz app does have a virtual reality component that will display items for sale in your home using the camera. It’s pretty cool.

As someone whose house was built with flat sheet mirrors, please don’t run a mirror from the edge of your shower to the edge of the mirror. It’s boring and unattractive. I am looking for bathroom mirrors myself and will remove the wall-to-wall sheet mirror from my half bath and MBa.

Ditto Marilyn B. I have the same boring full wall mirrors in all my bathrooms and I hate them. If the mirror is unusual and fabulous no one will notice the odd window to the left. You may want to scour antique, old furniture stores and flea markets. This one feature can bring pizzazz to your powder room.

Thanks for all your input! I don’t think we are doing any window treatment in this bathroom and would go for geomatics or oval shaped mirror.

Something like this or the second photo mirror and window shapes swapped.
I have a much better example saved in pinterest, but I can't find it in my boards at the moment.