Tons of bobbins for the Avente, extra needles for it in sizes 16, 18, and 20. Lots and lots of thread, muslin and/or cheap sheets to practice on.
I also have a peg board for my rulers and template I use on my HQ16. I like having paper and pencil near my frame to practice quilting design. Long tape measure and scissors , both small and large that stay at the frame. Wet erase markers, dry erase board and markers.
These are all things I have and use at my frame.