An easy-to-print and scalable wire spool system design. No support and no hardware, purely 3d printed, with a built-in wire clip.
A basic unit needs 1x ‘Side Panel’, 1x ‘Right End’, and 2x ‘Spool’. An expansion unit needs 1x ‘Side Panel’, and 2x ‘Spool’. You could attach unlimited units to the basic unit.
Version 2: added a wire clip in every unit to improve usability.