– orbed variant common in German-language sources alongside ⟨♁⟩ for the Earth and ⟨⛢⟩ for Uranus, so that most of the planetary symbols contain an orb; sometimes with horizontal barbs on the outer tines so that those look like an inverted omega, ⟨℧⟩.
– another common variant today; this form of Neptune's trident was used by Newton as a symbol for bismuth, before the planet Neptune had been discovered. Typefaces that use this form may harmonize it with Jupiter so that it looks like ⟨⟩ reflected on itself.
Ψ – Greek capital letter psi is sometimes used as a typographic substitute.
When the symbol has a cross at bottom and the tines do not bear barbs, it may be identical to variants of ⟨🝁⟩, an alchemical symbol for for quicklime.
As one of several alchemical symbols for bismuth, Neptune's trident is not attested with barbs on the tines, and is unlikely to have ever had a planetary cross or orb at bottom, but a distinct character is not available in Unicode, and it is identical to the design of the planetary symbol in some typefaces.
^ “Solar System Symbols”, in Solar System Exploration, NASA and the Planetary Institute, January 30, 2018, retrieved November 3, 2019: “The symbol for Neptune is the trident (long three-pronged fork or weapon) of Neptune, god of the sea.”