Printed fabrics

will look better longer than solids. A tiny dash of yellow, orange or pink in addition to the pale blue, green, navy, or gray would work.

You can get washable zip covers. Search by fabrics& size & colors .

I don’t get the widespread use of sewn-shut throw pillows that are never washed despite kids, dogs but eventually have to be thrown away, but usually only after they are beyond the “ freshness” date. Eewww! I have zip covers I’ve had for many years, wash carefully & air dry usually, and certainly saves not only money, landfills but also time finding the colors & patterns I like over and over.

They used to be mostly from places like Pottery Barn ( or custom made or DIY for those who sew- ) but now you can find some at discount stores, but it’s hit or miss as to what’s in the stores. Etsy , of course but I’ve found them at Target online, Home Depot ( their connections with a wide array of vendors in their online offerings.)

Perhaps it's your picture or my laptop but your walls look a pinkish beige colour so I've modified the colour to make them lighter. I've added/modified a few accents.

I got these in the exact size I needed from Etsy. I think they’ll look good on your couch. Most Etsy sellers will customize sizes.

I’d want a pair that is shaggy and creamy as a base, and then also something nubby with a pattern in your rug’s colors - this shop has good guides on sizes and numbers for sectionals

I would like to see one more color in that space so maybe this and a green throw too

I love your rug and letting it set the tone and be the star (vs being taken over) is the direction I’d head. Layering, different sizes and pattern is impactful and suggest soft, calm shades, which will also suit your sectional’s fabric. Add a cozy, washable ivory throw to curl up in.

Maybe try Etsy for washable covers and if the inside pillow isn’t really full, add extra stuffing. If you don’t have luck, HomeSense/Marshalls carry great cushions at decent prices. Look on line for help regarding placement, but using the corners is a nice look (see below).

Suggest art with a wood frame to create a connection to your coffee table.

You could do a simple scarf wrap. Go to your local thrift store or fabric shop and wrap around the pillow. Inexpensive, easy to change out and you can throw it in the washer. And you don't have to worry about the size.

Plenty of tips on Google.

Good luck! Have fun with it