Erasm++, the Embedded Runtime Assembler in C++, is an Embedded Domain Specific Language (EDSL) in C++ for runtime code generation on Intel 64/IA-32 architectures. It supports complete compile-time syntax checking, and its code generators run very quickly because necessary data are computed statically. Also included are GenericDsm, a fast and generic instruction decoder library which supports "pattern matching" against the decoded instructions, and MetaPrelude, a Haskell-like lazy metaprogramming library that helps implementing EDSLs in C++.
Bokken is a GUI for the Pyew and Radare2 projects. It provides an interface to almost all the features of Pyew, and many in radare2. It's intended to be a multi-architecture disassembler and binary analysis tool, and maybe some day an alternative for commercial alternatives as IDA Pro. Currently, Bokken is neither a hexadecimal editor nor a full featured disassembler, so it should not be used for deep code analysis or for modifying files.
Opdis is a wrapper for the libopcodes disassembler library distributed as part of GNU binutils. It extends the libopcodes library by offering linear and control-flow disassembly algorithms, instruction and operand objects that are suitable for analysis, and a command-line utility to perform disassembly on arbitrary locations in a file. The Opdis project consists of the libopdis library and the opdis command-line utility. There is a Ruby gem providing access to libopdis, and a supporting gem providing access to libbfd.
MCU 8051 IDE is a fully featured integrated development enviroment for MCS-51 based microcontrollers. It consists of a compiler, an advanced text editor (with highlighting, validation, and completion), a simulator, a scientific calculator, a hex editor, and many other things. Currently, this program supports only assembly language and a few microcontrollers.