He includes size-variation forms to aid with the reading of hieroglyphs in running blocks of text.
In contrast, for example, the Budge Reference has about 1,000 hieroglyphs listed in 50 pages, but with no size variations.
One example of this is 𓅒 G16, nbtỉ, the ideogram for the Two Ladies, goddesses Wadjet as the cobra and Nekhbet as the white vulture.
These are the protective and patron goddesses of the separate Egyptian kingdoms that joined into ancient Egypt, who were both then displayed on the uraeus of Wadjet when the unification occurred and afterward considered jointly to be the protectors of Egypt and the pharaohs.
Other subcategories included by Gardiner are abbreviations and personalized forms, and also a complete subset, used on papyrus, specifically for the Book of the Dead.
These hieroglyphs have unicode code points and so, given a suitable font, can be displayed or printed.