I would add pops of green, orange, or black. But I wouldn't use all or it might like really busy.

Love your choices!!!. For pillows, go with 16, 34 and 42 or 3, 28 and 33 as an example. No greys, nor dark blue. For sheets, I would stay with a solid color like fushia or sunny yellow...enjoy, this will look fresh !

It depends on what look you want to achieve as to what colors/patterns you would choose:
More playful, younger: 3, 33. You already have a pattern in the duvet/pillow.
Op-Art Sophisticated: 7, 18, 36
Mid-Century: 9, 41
With an intense color like that pink, yellow/aqua/red/orange won't work as well.

you have 2 pink and white fabrics there now. I recommend sticking with the same colors....hard to tell which is the closest #2, 3, or 8? Adding another color would look really busy....to much for a calm bedroom you have already going for you. Hope this helps! :)

I think this could get very fresh and sophisticated using 36 and 30 (reverse image black and white prints) and painting your walls a soft pale gray. You might be able to add a solid clear turquoise as an accent here and there.

And do use solid color sheets...pink, white, turquoise (maybe)...you will want to play with it bit to get the right balance. Could look OK with pale pink walls, too

What a fun duvet! We would definitely complement the pink with solid gray (slightly older), yellow (more bright and fun)) and a lighter or darker/hot pink (younger) sheets. If you love patterns on sheets, make sure that they are smaller in pattern so they do not overwhelm the duvet cover. The stripes should stand out and be the main focus of the bedroom.

If you are still unsure about mixing and matching contrasting colors and patterns, another idea that could make the bedroom more interesting is to add textures to the bed - like a solid ruched or a pintuck pillows in the back.

I feel the duvet cover will be highlighted by adding plain sheets ,picking up colour from one of the panels.a strong col will look stunning

you have to mixe 20- 3--7-9 .

What a fun problem to have! I would pick your favorite color and go with two pillows in your favorite pattern and then one pillow in your second favorite. Mine would be two 16s and one 22. Or maybe two 39s and one 38. Or maybe.... As you can see, I don't think you can go wrong if you pick colors and patterns you like. They go well together. You made a great choice picking this source.

I would eliminate all of the zig zag pattterns as too similar to the wide stripe of the comforter and sham. Sheets in pattern 2 would be precious for a little girl. Sheets in pattern 22 would be more energetic and current for a teen, and sheets in pattern 29 would appeal to more sophisticated tastes.

Are you familiar with textile designers such as Kaffe Fassett, Amy Butler, etc? They do a lot of quilting and home decor fabrics in very contemporary geometric and floral designs and eye popping colors. I definitely recommend checking them out to expand your options. If you aren't able to construct the pillows yourself, you can find a local artisan to make them for you. Check out Hancocks of Paducah on line for these and other contemporary cotton fabrics...(not to be confused with the chain Hancocks fabric stores.) This source carries a lot of black and white fabrics as well. I like several of the options in the textile line you've illustrated, but am afraid there is too much "sameness" in the scale and patterns to give you both the bold simplicity and "pop" you seem to be seeking. Hope this is helpful. Best of luck...and enjoy the process!

#33 and #22 would look nice as pillows with that duvet.

I agree w/Dana Veach in that it might be good to expand your search for companion fabrics. The Textile Files on Pinterest is such an inspiration, and the fabrics are beautifully curated. Love the bold horizontal stripes in the duvet cover. Perhaps add a bit of contrast and interest with round, organic shapes in a contemporary motif. Lastly, try introducing a fabric that deviates from the one color + white.

If you like fresh do white sheets and maybe a pretty throw in green .