This is a herringbone (a version of the double helical) gear rack and pinion, remixed from a single helical rack and pinion by janssen86. The doubling up of the helical teeth removes the axial thrust of a single helical gear and also helps keep the gear centered.
I printed a test print prior to using this as a component of a bigger project, but found that both I and my kids also enjoyed this as a fidget toy! There is something quite satisfying about how nicely the pinion stays on track on the gear.
No supports needed. I printed at 0.20mm resolution with a 0.40mm nozzle. Note that in the current version (not the one I printed) the pinion prints upside-down relative to the rack. This is deliberate, as the bottom side gets squashed a little, and this should symmetrize the squashing. The squashing made my test print not align so nicely. I should do another test print at some point.