https://github.com/adobe-type-tools/afdko/ Adobe Font Development Kit for OpenType
https://github.com/mpcabd/python-arabic-reshaper/ Reconstruct Arabic sentences to be used in applications that don't support Arabic
https://github.com/simoncozens/babelfont Abstract interface to font source files based on fontParts
https://github.com/BlackFoundryCom/black-renderer Python-based renderer for OpenType COLR fonts, with multiple backends
https://github.com/simoncozens/beziers.py/ A library for constructing, manipulating, and drawing general Bezier curves and paths
https://github.com/aparrish/bezmerizing/ A library with some potentially helpful classes and functions for working with Bezier curve functions
https://github.com/typemytype/booleanOperations Boolean operations on paths.
https://github.com/adobe-type-tools/cffsubr Standalone CFF subroutinizer
https://github.com/simoncozens/collidoscope Brute force detection of glyph collisions
https://github.com/googlefonts/compreffor A CFF subroutinizer for fontTools.
https://github.com/pgmmpk/cslavonic Utilities for working with Church Slavonic language
https://github.com/googlefonts/cu2qu Cubic-to-quadratic bezier curve conversion library
https://github.com/robotools/defcon A set of flexible objects for representing UFO data.
https://github.com/trufont/defconQt A set of Qt objects for use in defcon applications.
https://github.com/source-foundry/dehinter A tool to remove TrueType instruction sets (hints) from fonts
https://github.com/goodhertz/drafting Color and geometric primitives
https://github.com/justvanrossum/fbdiff Show a summary of table differences between two OpenType fonts.
https://github.com/source-foundry/fdiff An OpenType table diff tool for fonts.
https://github.com/source-foundry/font-v Font version reporting and modification tool
https://github.com/googlefonts/pyfontaine Font analysis tool for determining character/glyph support
https://github.com/googlefonts/fontbakery Font-project QA application
https://github.com/fabiocaccamo/python-fontbro Friendly font operations
https://github.com/googlefonts/fontcrunch/ Simplify splines using the fewest points, without distorting contours
https://github.com/googlefonts/fontdiffenator Font regression tester for Google Fonts
https://github.com/simoncozens/font-engineering A collection of font engineering utilities
https://github.com/simoncozens/fontFeatures Python library for manipulating OpenType font features
https://github.com/source-foundry/font-line Vertical metrics reporting and adjustment tool
https://github.com/source-foundry/font-ttfa A command line tool for reporting TTFA table data from fonts hinted with ttfautohint
https://github.com/googlefonts/fontmake Compile fonts from sources (UFO, Glyphs) to binary (OpenType, TrueType).
https://github.com/robotools/fontMath A set of objects for performing math operations on font data.
https://github.com/codesigntheory/fontmeta A utility to get ttf/otf font metadata
https://github.com/robotools/fontPens A collection of classes implementing the pen protocol for manipulating glyphs.
https://pypi.org/project/font-reducer/ A toolkit for reducing font size.
https://github.com/whtsky/font-rename/ Rename fonts to match internal name metadata and unpack .ttc/.otc collections
https://github.com/source-foundry/font-size File- and table-size reporter
https://github.com/googlefonts/gftools Assorted tools for working with the Google Fonts library
https://github.com/googlefonts/glyphsLib A bridge from Glyphs source files (.glyphs) to UFOs
https://github.com/schriftgestalt/glyphs-packages Repository to collect all available plugins for GlyphsApp
https://github.com/simoncozens/glyphtools Routines for extracting information from fontTools glyphs
https://github.com/Muda42/gsbuild Compiler for Google's Product Sans font
https://github.com/rosettatype/hyperglot Detect language support for font binaries
https://github.com/jenskutilek/jkFontGeometry Font-related geometry tools
https://github.com/adobe-type-tools/kern-dump/ Scripts for working with and analyzing kerning information
https://github.com/font-bakers/knead A command line tool for preprocessing, manipulating and serializing font files for deep learning ...
https://github.com/SeokminHong/korsubset An easy font subsetting tool for Korean fonts.
https://github.com/laziu/krwftgen Korean webfont generator using Google Fonts
https://github.com/Tarobish/Mirza Utilities used to maintain the Naskh body-text font Mirza
https://github.com/LettError/MutatorMath/ Python for piecewise linear interpolation in multiple dimensions with multiple, arbitrarily place...
https://github.com/mdileep/mutatorMath.gui An attempt to create web-based GUI for MutatorMath
https://github.com/loicsander/MutatorScale Tool for interpolated glyph scaling, based on Robofab, FontTools, MutatorMath & BooleanOperations.
https://github.com/googlefonts/nanoemoji Compiler for color fonts
https://github.com/googlefonts/nototools Scripts used to maintain the Noto Fonts project
https://github.com/twardoch/fonttools-opentype-feature-freezer/ Turns OpenType features 'on' by default in a font: reassigns the font's Unicode-to-glyph mapping ...
https://github.com/adobe-type-tools/opentype-svg Tools for building SVG-in-OpenType fonts
https://github.com/awesometoolbox/otf2ttf Command-line tool for converting OTF to TTF
https://github.com/Pal3love/otRebuilder A command-line tool for OpenType standardization with multi-language support
https://github.com/source-foundry/panosifier Edit the PANOSE fields in a font's OS/2 table
https://github.com/source-foundry/path-inspector Inspect quadratic paths in fotn contours
https://github.com/adobe-type-tools/psautohint Python wrapper for Adobe's PostScript autohinter
https://github.com/adobe-type-tools/python-modules/ Python modules from Adobe for writing kerning and mark features and for supporting FontLab scripts
https://github.com/silnrsi/pysilfont Tools to support font development, with an emphasis on UFO-based workflows.
https://github.com/jansindl3r/sameWidther Gets random words of the same width for given font
https://github.com/MFEK/sfdLib.py Converts FontForge .sfd font sources to .ufo format
https://github.com/fonttools/skia-pathops/ Python access to operations on paths using the Skia library
https://github.com/source-foundry/Slice GUI app to generate custom font design spaces from variable fonts
https://github.com/daltonmaag/statmake Generate STAT tables for variable fonts from .stylespace files
https://github.com/simoncozens/tensorfont Turn font glyphs into numpy arrays
https://github.com/TiroTypeworks/TiroTools Assorted font production scripts, mostly involving either conversion of data between font development source formats, or manipulation of source formats.
https://github.com/trufont/trufont TruFont, a modular and cross-platform font editor.
https://github.com/trufont/tfont tfont is a font library that writes to JSON.
https://github.com/johncf/ttf2web A tool to optimize fonts for web distribution.
https://github.com/mcfletch/ttfquery Library for finding fonts and building render-able outlines from the glyphs
https://github.com/googlefonts/ufo2ft A bridge between UFOs and FontTools objects (and therefore OTF/TTF).
https://github.com/robotools/extractor Tools for extracting data from font binaries into UFO objects.
https://github.com/fonttools/ufoLib2 Thin UFO font-processing layer built on top of ufoLib.
https://github.com/LettError/ufoProcessor Read, write and generate UFOs with designspace data.
https://github.com/LucasFonts/vfbLib VFB-to-UFO3 converter and normalizer
https://github.com/jonpalmisc/vfit Generate backwards-compatible, static instances of variable fonts
https://github.com/simoncozens/vharfbuzz Python interface to uharfbuzz
https://github.com/daltonmaag/vttLib Compile Visual TrueType assembly with FontTools.