Hecate - Hecate is the smart hex editor designed for Windows, Mac OS, and Linux.
BinHex CryPactor - Manipulate binary and hexadecimal strings!
Hex Workshop - Hex Workshop: Hex Editor, Sector Editor, Base Converter and Hex Calculator for Windows
HextEdit - HextEdit is a proficient hex editor and disassembler for Mac.
PilotEdit - PilotEdit Lite is an advanced text and hex editor that supports opening of files larger than 4GB.
Heme - Heme is a best in class hex editor and disassembler for UNIX systems that enables you to edit, disassemble, debug, and analyze binary files.