Nothing. Every space doesn’t need something in it.

You could, though, get a bigger bedside stand. That one looks kinda small and short and it‘s pretty full.

Bigger nightstand, bigger lamp, maybe drapes on window.

Please post more pictures, especially of that entire wall with both sides of the bed shown. That way, we can clearly see what you’re working with.

New nightstands are not an option at the moment, but here is the full wall.

Your lamps are way too small, and move the pictures closer together. Pillows should reach 2/3 of the way up the headboard.

Is the bed centered between the door(?) on the right and the wall on the left? If not, that will help. Agree that tables and lamps should be larger. They don’t have to match (mine don’t) unless you prefer the matchy match look.

Will that help with the corner space though?

If you center the bed, you’ll eliminate most of that space. It appears to be right up against the door.

Yes, the bed is centered on the wall

But it is not centered between door and window. Try that, unless there’s a reason you can’t.

You’ll get the best advice I’d you draw a to-scale plan of the room, with dimensions, noting all windows, doors and closets.

Love your kitty cat! By moving the furniture over just a bit, it will actually make the space seem larger as the nightstands and bed will have breathing room and not look crowded against the door. This will make use of that empty space, and the remaining room there will again help to establish a roomier, more open feel. Give it a try and post another picture so we can help again.

Drapes will help

Much bigger lamps, and draperies. Nothing else is needed in the corner. Also - try placing the pics above the bed closer together and lower.