Nice couch and flooring! I would choose the lightest color leather for the ottoman. It would compliment the couch and flooring beautifully. I would fear a darker colored leather ottoman would stick out like a “sore thumb”. Best of luck on your journey!

I vote for the second lightest one so there is some contrast with the floor since you're not going to have a rug.

The yellow tan is the same color as your pillow, and the pillow is the only thing that matches any of the leather colors. You can change the pillow, of course.

The second lightest one looks like it works the best

Why show the leather on the floor, when the area rug needs to be added to the mix?

I'll bet there is a matching ottoman that coordinates with that sectional. That's what I would recommend you purchase and then place a sliding "over the ottoman" cocktail table to make the space work best.

Or you could select a more exotic ottoman and still have a coffee table slide over the ottoman so the space is functional.

Here is a tufted leather ottoman with a marble table that slides over the ottoman.

Rather than a large ottoman, I'd consider 2-3 small glass nesting tables. The glass will visually open the space. If you are looking for additional seating via an ottoman they can be difficult to use as they don't usually have much support. If this is your thinking I'd opt for large floor pillows that can rest on the outside of your couch until needed. Or get a couple of good poofs that are easily moved around the room, or even another room.

2

2. It picks up on nice high lights in your floor. It is a color that feels most neutral to me so you will be able to switch out pillows, artwork, throws over time. I did no area rugs because of allergies for a long time. I appreciate the need and think you are creating a great looking space.

You have allergies but a cloth sofa interesting. As for the color for the ottoman how about the cognac color like the pillow . There is no context to really help with this what are the spaces like around this IMO other than bedrooms living spaces need some connection to each other .

Looks like a nice cosy little corner...

I find #4 seems to be a nice tan that coordinates nicely with your hardwood floors. All you'll need to complete your decor is artwork on the wall.

I like #3 and #4. They both contrast nicely with the floor and work with the sofa and pillows.