I would do a mustard yellow linen duvet:

Then, I'd add in some rustic wood accents.

That looks like a cool rug, and it gives you numerous choices for bedding color. I like the mustard yellow suggestion above. What are the other colors in this room going to be?

I like the yellow too.

Just pick one of the colors from the rug and do the bedding in that solid color. The yellow looks good but you have other options if that one doesn't suit you

This is in a huge extra bedroom that my granddaughter sleeps in sometimes. The bed and dresser is black from Ikea. Guess I am stuck with something solid. Can add some colorful pillows.

Or go bonkers and do black and white polka dots, stripes, or other pattern and those colorful pillows. I wouldn’t choosecthe mustard color...just me.

I would rather go bonkers like you suggest. Solid comforters are just boring. So maybe a small polka dot pattern since the diamonds are big?

Yep, when you are mixing patterns, changing the scale is one of the tricks to get things to go. A small pattern, large color-blocking, a tone-on-tone pattern using one of the colors from the rug, or a large stripe could all work.

These are from The Company Store.

I like the idea of black and white with your rug:

depending on whether the reds match, this might work,

re

The rug makes me think of otomi. I think a nice otomi bedspread in a small print would look fun and also lovely, particularly if you keep the rest of the room relatively simple.

Oh my gosh I love this! Yes, the rest of the room is very simple. May or may not even have window treatments. Want something fun my granddaughter will like, yet not too terribly "kiddish."

That Otomi Claire shared is a brilliant option!