This is a common misconception. Intergalactic space is filled with about half of the matter in the universe. See: https://en.m.wikipedia.org/wiki/Warm–hot_inter

This is a common misconception. Intergalactic space is filled with about half of the matter in the universe. See: https://en.m.wikipedia.org/wiki/Warm–hot_intergalactic_medium https://en.m.wikipedia.org/wiki/Warm–hot_intergalactic_mediu... As to your original point though, there doesn’t appear to be too many elements here apart from ionized hydrogen and hydrogen.