I can post what I might try, but tell more about the room: size of, and furniture for it, etc... fun and seems a blend with floor color. Might be nice with furniture having stick legs....

Safavieh Porcello PRL7731D 8'2"x11' Dark Gray, Ivory Rug · More Info

Teal, gold, turquoise and ivory. Finely constructed from 30% Corn fiber, 70% Polyester.

Nourison 2020 NR202 Area Rug, Teal, 6'6" x 9'5" · More Info

https://www.houzz.com/products/2020-area-rug-teal-66x95-prvw-vr~101289586

Maybe a sofa in livelier neutral, or other: this with good reviews?

Jute Simple Border Area Rug, Gray, 8'x10' · More Info

[https://www.houzz.com/products/jute-simple-border-area-rug-gray-8x10-prvw-vr~89429491[(https://www.houzz.com/products/jute-simple-border-area-rug-gray-8x10-prvw-vr~89429491)

I would do something plain and neutral so as to take away from the business of the flooring and make the furniture more interesting with patterns.

I'd also recommend sticking with a somewhat neutral area rug. I've been looking at replacing my area rug and have found some nice options at Target.com with their Project 62 line. You didn't mention a budget, however they're all reasonably priced. If you purchase a rug from there and you don't like it in your space it's easy to return it back to the store. I'll include two photos of the ones that might look nice in your space. Also, just throwing this out there...have you thought about painting your brick fireplace white? :) My sister painted her fireplace white and it looks fresh/bright. Good luck!

Here's a project 62 - Elle Ikat rug.

My apologies, I can't get the photos to show up. One was the Project 62 Elle Ikat rug - charcoal heather and the other is the Glacier Diamond Rug - Project 62 in grey, cream or charcoal heather.