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.
Boomerang is a decompiler that takes executable files and attempts to create a high level, compilable, possibly even maintainable source file that does the same thing. It does not matter if the executable file has symbols or not, or whether it was compiled using any particular language.
Chump is a table-driven assembler and dissembler with a very fast new architecture input format. Both the assembler and disassembler are created using a single description. It comes with descriptions for ARM, MIPS, Stump, and 6809. It is intended for use as a library compiled with other programs to allow line assembly and disassembly.
Classfile Reader & Writer is a Java package that makes it easy to read and write Java class files. It does not provide any help with displaying the contents of a class file (besides debug output) or disassembe the byte codes, but can read "obfuscated" class files such as those generated by Crema.
DIOTA is a just-in-time instrumentation tool for Intel binaries. It allows you to create a dynamic loadable library that can be attached to a program running under Linux. DIOTA can instrument all memory operations in the application and the used libraries (e.g., for checking for faulty memory accesses), calls of dynamically linked procedures (malloc, printf, etc.), detect the code executed during a particular run, and more.