Python-based GUI to configure fetchmail

https://www.fetchmail.info/

Realtime audio/video encoder/converter and streaming server

http://ffmpeg.org/

Lightweight video thumbnailer that can be used by file managers

https://github.com/dirkvdb/ffmpegthumbnailer

FFmpeg-based source library and VapourSynth plugin

https://github.com/FFMS/ffms2

FFmpeg version of Nvidia Codec SDK headers

https://github.com/FFmpeg/nv-codec-headers

Fast C routines to compute the Discrete Fourier Transform

http://www.fftw.org/

Fast Discrete Fourier Transform (Single Precision C Routines)

http://www.fftw.org/

Fast Discrete Fourier Transform (Long Double Precision C Routines)

http://www.fftw.org/

Integrated benchmark program

http://tromp.github.io/c4/fhour.html

Easy to use graphical editor for electronics

https://darwinne.github.io/FidoCadJ/index.html

Small, efficient C++ GUI library designed for games

http://fifengine.net/

Narrow monospaced fonts

https://fontlibrary.org/en/font/fifteen

Tools to convert Xfig .fig files

https://en.wikipedia.org/wiki/Xfig

Tcl/Tk-based filemanager with FTP capabilities

https://sourceforge.net/projects/filerunner/

Fast and reliable cross-platform FTP, FTPS, and SFTP client

https://filezilla-project.org/

Finch multi-protocol messaging client (Console UI)

https://www.pidgin.im/

GNU find utilities

https://www.gnu.org/software/findutils/

Flexible IO tester

https://git.kernel.dk/cgit/fio/

Sans-serif, monospaced, and code typeface for small screens

https://bboxtype.com/typefaces/FiraSans/

Monospaced font with programming ligatures derived from Fira

https://github.com/tonsky/FiraCode

Expanded version of Fira Sans with support for additional languages

https://bboxtype.com/typefaces/FiraGO/

Combination of two Arphic Sung fonts

http://www.study-area.org/apt/firefly-font/

Firehol ip list downloader

http://iplists.firehol.org/

Create device firmware images

https://www.openwrt.org/

Expand / when the system first boots

Update the system using midnightbsd-update when it first boots

Install packages when the system first boots

User friendly command line shell

https://fishshell.com/

Form a line of 5 or more colored balls

https://wiki.gnome.org/Five%20or%20more

Patch making it possible to embed PNGs into RTFs

Free lossless audio codec

https://www.xiph.org/flac/

Backup content from any volume to a tarball

https://github.com/laffer1/flashback/

Memory efficient serialization library

https://google.github.io/flatbuffers/

Fast lexical analyzer generator

https://github.com/westes/flex

Small run-time speech synthesis engine

http://www.festvox.org/flite/

Manage locks from shell scripts

https://www.kernel.org/pub/linux/utils/util-linux/

Floating point benchmark to give your MFLOPS rating

http://performance.netlib.org/performance/html/flops.html

Suite of tools and library to work with netflow data

https://github.com/5u623l20/flow-tools/

Dictionary for flowers (EPWING V1 format)

http://openlab.ring.gr.jp/edict/fpw/

Cross-platform C++ graphical user interface toolkit

https://www.fltk.org/

Real-time software synthesizer based on the SoundFont 2 specifications

http://www.fluidsynth.org/

Small and fast window manager based on BlackBox

http://fluxbox.org/

Tenner themes pack for fluxbox

http://tenr.de/styles/

Legacy FreeBSD pmake

Missing font manager for UNIX

https://github.com/alexmyczko/fnt

Show Unicode coverage of a font

https://github.com/eugmes/fntsample

Free On-line Dictionary of Computing (EPWING V1 format)

http://openlab.ring.gr.jp/edict/fpw/

Library to aggregates people from multiple sources

https://wiki.gnome.org/Projects/Folks

X.Org Adobe 100dpi font

http://www.x.org/

X.Org Adobe 75dpi font

https://www.x.org/