Similar to Apache_Commons_Email

Exa (command-line utility)

Exaile

Expr

EZ Publish

F-Spot

Falkon

Far Manager

Fast Library for Number Theory

Fetchmail

Ffdshow

FFmpeg

Fastest Fourier Transform in the West

FIGlet

File System Visualizer

Filesystem in Userspace

FindBugs

Firebird (database server)

Firestarter (firewall)

Firewalld

Flask (web framework)

Flatpak

FLTK

Flutter (software)

FMSX

Foliate (software)