To maintain the design, perhaps sashing around a set of four blocks is a great way to expand a block. I've seen some sash in a small way, say about 1/2" between in the center of the four patch blocks, creating a "+" sign, then larger sashings surrounding the 4 patch blocks.
Multiple sashings giving it a log cabin effect is another way to enlarge. You would actually be using your blocks as the log cabin center. The blocks could be as large as you want.
Another idea - use a really large sashing & incorporate some applique or embroidery on the strips.
If you have a focus fabric that incorporates your colors, you could actually do some "big blocks" and do some elegant designs with that, using the 4 patches of yours & 1 big block in an offset design, thus making an "x" type effect in your quilt.
Pinwheel blocks are fun ways to do an alternative quick block to add another design element to your design.
I do like your blue blocks. Let us know what you come up with.