As far as commercial helmet liners, what brands and models do you recommend for an ODST helmet and why?
i couldn't get a motorcycle liner readily available at a store so instead i picket up a dirt biking helmet liner with a few sticky pads on the front for the forehead and it's working perfectly. motorcycle padding seem to be a better choice if you can fit them into your helmet.
Best idea i could come up with is military helmet padding. You can order a kit, it comes with velcro circles with adhesive on the backside, and pads with velcro loops on the backside, a big round center piece, forehead piece, and several support pieces, and can be arranged for better fit or better airflow. You would probably be able to find it if you search for "ACH padding"