Madbury - - -
In your pic, from left to right, I would say all but the second fabric (the teal w/ the gold flowers). Any of the other fabrics would be great.
wildyard - -
I'm so excited you're thinking about jumping in (but careful with that knee!) lol
I think it would be better to underestimate the number of sets than to OVERestimate. Worst case scenario - you might end up getting some of your own blocks back.
For the fabric color choices, please use either a white or a white tone-on-tone to make the four-patch. Please follow the cutting instructions in the link; 1 inch on either side of the center seam. In future swaps, we might mess around with the cutting instructions. For this one, let's keep it all the same. That way, our quilt blocks will all play well together.
We will definitely be using other themes and color combinations in future swaps. I am always happy to have ideas and suggestions as others have posted. Keep 'em coming gals!