Would these work?

[littlemisscomper]

This rug:

www.ikea.com/gb/en/products/textiles-rugs/rugs/s%C3%B6nder%C3%B6d-rug-high-pile-blue-art-00345846/

With this sofa:

www.ikea.com/gb/en/products/sofas-armchairs/leather-coated-fabric-sofas/vimle-3-seat-sofa-farsta-black-spr-59206886/

They would be in a small living room, off-white walls and wood style laminate floor.

Have you measured the room? The sofa is 241cm wide so it's needs a big room.
I'd also re-think having very pale walls and a black sofa as strong contrasts make spaces appear smaller.

Thanks for replying JoJo. Actually, it's not that sofa at all - it's just a black leather sofa that my brother has already got. I'm getting him a rug for Christmas (he's just moved in to his new house). I just linked to the Ikea sofa so people could imagine the black leather sofa/blue rug look. Do you think it would clash?

I would ask him what style and colours he fancies tbh. Also that rug is big so the size would work with the linked sofa. If his sofa is smaller, it might be too big.