The library

Cross-platform

fontTools.t1Lib
Provides a Type 1 font reader. Writing is a planned feature.
fontTools.ttLib
Extensive TrueType tools. Reads and writes. This is the flagship of FontTools, it’s by far the most mature component. Contains a completely modular TTF table converter architecture. See ttLib/tables/table_API_readme.txt.
fontTools.afmLib
And AFM file reader/writer.
fontTools.cffLib
Reads CFF fonts. Writing is a planned feature.
fontTools.unicode
A simple (but large) module that translates Unicode values to their descriptive names. Still Unicode 2.0.
fontTools.agl
Interface to the Adobe Glyph List: maps unicode values to glyph names and back.

Mac-specific

fontTools.fondLib
A reader/writer class for Mac FOND resources.
fontTools.nfntLib
Reads Mac NFNT bitmap font resources.