This directory contains all three freeware logic fonts for the Mac that I know of, apart from fonts for use with TeX:
What I don't have is fonts for older logical notations - like the original notation of Whitehead and Russell's Principia, Lesniewski's symbols, or some of Peirce's oddities. I also don't have symbols for the relational algebra (as used in database theory) or for some of what Tarski and Givant use in A Formalization of Set Theory Without Variables. If you know of freeware versions of these, or have a spare copy of Fontographer you can give me so I can design them, please let me know and I'll link to them or add them to the archive.