The SimulAVR program is a simulator for the Atmel AVR family of microcontrollers (ATtiny and ATmega). SimulAVR can be used either standalone or as a remote target for avr-gdb. There are interfaces for Python and Tcl. When used in gdbserver mode, the simulator is used as a back-end so that avr-gdb can be used as a source level debugger for AVR programs.
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.
airbag_fd provides drop-in crash handlers for POSIX (particularly for embedded Linux). It dumps registers, backtraces, and instruction streams to a file descriptor. It is intended to be self-contained and resilient. Where possible, it will detect and intelligently handle a corrupt state (for example, jumping through a bad pointer or a blown stack). The harvesting and reporting of the crash log is left as an exercise for the reader.
dwarves is a set of tools to inspect the DWARF debugging information inserted in ELF binaries by compilers such as GCC, and which are used by well-known debuggers such as GDB and more recent ones such as systemtap. With pahole, the struct packing and cacheline efficiency can be inspected.