Pretty quilt. I like Julie Paschkis, she always comes up with wonderful fabric designs. I have several of her cat inspired fabrics.
If you choose the right custom quilter I am sure they can offer you plenty of suggestions. Ditching and dense background quilting gets elements to pop in any quilt. If this quilt came to me, I would definitely ditch the panel blocks and all the parts of the pieced blocks. I would outline the picture elements (fish, mermaid lantern and moth) in the panels. I would create a secondary unified design using ruler work in the gold but not the gold in the butterfly blocks. I would need to sketch a while to come up with some ideas. On the two star blocks on the side I would need to know if you want the star to stand out or not, that would impact my quilting choices. In the turquoise setting triangles I would also do some ruler work, probably lines replicating the triangle shape with some nice fill work in between lines, this would replicate elements used in the gold areas. Your outer border is busy fabric so nothing fancy will show there. Probably piano keys with possibly a fill in every other key. Or do a beadboard type piano key. The inner red/turquoise border I might treat as one unit.
Coming up with design elements on the fly is usually not my style. I usually need to sketch several designs motifs and decide what fits the quilt best taking into consideration your likes and dislikes.