Astronomical Mars moon Phobos symbol. The symbols for them are based on the lower-case versions of the Greek letters Phi and Delta, which begin those two names in the original Greek, with the arrow from Mars's symbol added on.
Alchemical symbols arranged with alphabetical correspondences. This is available as a free True Font download for your PC at dafont.com. The font is called Agathodaimon - type that in the search box at the site, Another excellent set of characters for secret writing in a Book of Shadows.