FileAlyzer!

wxHexEditor is an open source cross-platform disk/sector/file hex editor written in C++ with a wxWidgets-based user interface.

PE Explorer lets you look inside a variety of different 32-bit Windows executable file types, such as EXE, DLL and ActiveX Controls, perform static analysis, reveal a lot of information about the function of the executable, and collect as much information about the executable file as possible, without executing it. PE Explorer provides functions for disassembly and inspection of unknown binaries, modification of the properties of executable files, plus resource editing and translation features.

010 Editor is a professional text/hex editor designed to edit any file, drive, or process on your machine. Using Binary Templates technology, 010 Editor allows a binary file to be parsed into a data structure that can be understood. Features an editor with standard Cut, Copy, and Paste commands, support for huge files, and unlimited Undo and Redo for all editing operations. Use the Inspector to easily edit data in a number of different formats.

HexEdit is a hexadecimal file editor for Microsoft Windows. HexEdit allows the user to view and edit any type of file, no matter what format it is saved in.

Bless is a high quality, full featured hex editor. It is written in mono/Gtk# and its primary platform is GNU/Linux. However it should be able to run without problems on every platform that mono and Gtk# run on.

Kaitai Struct is a declarative language used for describe various binary data structures, laid out in files or in memory: i.e. binary file formats, network stream packet formats, etc.

You got a binary file and don't know its contents. Or some software creates binary files where you have a specification but don't want to decode them manually.

The professional Hex Editor for Windows and Linux.

Open Source powerful and flexible Hex-Editor, with multiple colour-schemes that allow easy visual indication of byte-magnitude.

DataWorkshop, a flexible, multiplatform binary data editor written in java.Implements power structure definition tool that allows to describe complex data structures inside files using loops and condition.