A Hex Editor for Reverse Engineers, Programmers
Third-party TI-84 Plus CE / TI-83 Premium CE emulator
Open-source disassembler for x86/x64 machine code (New BSD License!)
An assembler and disassembler for the JVM (Java Virtual Machine)
powerpc disassembler/assembler
Java classfile assembler/disassembler and interactive low-level editor
Binary (hexadecimal) editor for Windows