Love this one … those ghost blocks fill in space which otherwise would require a quilting design … and I would use them as the quilting design anyway.
The second one does have some space for quilting to shine, and I have two options I would consider … using the centre block design as a quilting pattern, or using one of the pieced blocks, probably the one in the corners.
When I started quilting (mid 1980s) we had limited design sources, and I started making up my own pretty much straight away. I, and others around me at the time, considered any line drawing was fair game when looking for applique and quilting designs.
I found that what appeared on the back of a quilt when you simply outlined the applique and pieced designs on the front made some very interesting quilting designs on the back. If the pieced and applique blocks work with colour on the front of a quilt, there is a fair chance that the design will look good with just the lines quilted. In the pieced blocks we can ignore some of the lines which are seam lines necessary for piecing the block together.