I was wondering if the quilt was one of the panel type ones, those are super hard for me to figure a quilting design for, I think the wood grain option works with many of them, along with similar designs that can look like water ripples or clouds.
I know you are looking for something other than all-over, but I think snowflakes could be very nice all over. Whether an all-over meander like this one:
https://www.urbanelementz.com/deb-s-...s-meander.html
or maybe more linear like this one:
https://www.urbanelementz.com/snowfl...d-ribbons.html
You can also construct vertical/horizontal designs doing half on a line going one way and half on a line going the other -- I know, something that would make more sense if I just drew it out.
You could reinforce the grid and only do the meander type in the blocks and still be able to skip from block to block pretty easily with a long arm.
Often the quilting I wish to do is fancier than I can draw and with my vision issues I have problems following markings on the fabric. I will buy parchment paper at the dollar store and copy a pantograph pattern onto the paper with pencil and then either quilt through the pencil or "presew/paper punch" the lines and following the dots. Yes, you have to do extra work to trace everything and then yes, you have to take off the paper, but that's what I need to do when doing a complex design over a heavily patterned surface.