I would leave it empty and add art to the walls as suggested

Nothing on the floor. Art...or go crazy with a fab wallpaper. Room needs to be warmed up, imo.

Framed prints on the large wall and a towel rack with lux towels opposite sink.

Since it's a powder room you don't really need more storage, so art is the answer. I would also either paint the room a color instead of leaving it white, or wallpaper, which is popular in powder rooms. I just hate hanging and removing wallpaper, so I went with blue walls in mine, and hung a pair of peacock prints to add color. Look to adjacent spaces for color cues. Lots of colors would work with what's there.

Seaside Bungalow · More Info

Wallpaper could be a nice addition to this room.

Nothing in the corner but wallpaper would be awesome and I love the giant print ones in PRs since that is one space in a house you can go a bit crazy .

Yes,wallpaper is a distinct possibility,but good luck with making that ultimate choice.
Big art is always eye pleasing.
Although most PR usage times are short,gaze worthy art like intricate designs or maps can enhance the ambiance..
Leave the corner empty...no need for clutter and extra swabbing of stuff.