How about a wall decal?

Is this a high traffic area? Where do you go if you go out that door?

Yes, the photo is taken from the front door. The door ahead is a coat closet and the door to the right is the garage entrance. A little cramped :-/

Not every space needs to be filled.
sometimes less is more ;-)

I wouldn't put furniture there, but agree with najeebah that a bigger rug that covers more of the tile would look warmer and doesn't visually divide the space in half. You could try to turn this rug lengthways. Do you have some lovely art hanging on the stairs wall? A nice chandelier/pendant/ceiling fixture?

Add artwork on the coat closet door. Something simple yet significant. Google: hanging artwork in small areas

I would not add any furniture in that space. A larger area rug is all that is needed.