Beautiful colors! You should be so proud of yourself - a bed sized quilt, already! Yay, you!!!!!
I think you're right to want some round-ish quilting designs for this linear pattern.
Amy Johnson has a lot of FMQ design tutorials - if you're up for a bit of a challenge and some great practice, I would go with something like these feather flowers within the center of the quilt - and then look for her videos for filling defined squares and triangles with feathery designs to coordinate.
https://www.youtube.com/watch?v=UWqKBhlZjs4