Here are some excellent companion tools for FLEx, which are designed to do things you need to accomplish, which FLEx doesn’t cover:

Automated Backup
MyWorkSafe
RAMP SIL Archives

Import-related
SheetSwiper
SOLID

Text transcription and time-alignment
SayMore
ELAN

Phonology
Phonology Assistant

Publishing
Pathway
PDFDroplet
XLingPaper
FLEx LibreOffice interlinear exporter
OpenOffice Linguistic Tools (for OpenOffice and LibreOffice)
Kratylos Publishes LIFT (dictionary) and FlexText (interlinear) on a website with links and queries between them.
Webonary To create an online Dictionary from FieldWorks data.

Simpler user interface for entering lexical data
WeSay

Web based interface for lexical data
Language Forge

Send/Receive
ChorusHub

Rule-base machine translation based on FLEx
FLExTrans

Various uses
FLExTools An application for running Python scripts against a Fieldworks database