RetDec is a retargetable machine-code decompiler based on LLVM
...Detection and reconstruction of C++ class hierarchies (RTTI, vtables). Signature-based removal of statically linked library code. Static analysis of executable files with detailed information. We currently support Windows (7 or later), Linux, macOS, and (experimentally) FreeBSD. An installed version of RetDec requires approximately 5 to 6 GB of free disk space.
BEYE (Binary EYE) is a free, portable, advanced file viewer with built-in editor for binary, hexadecimal and disassembler modes. It contains a highlight AVR/Java/i86-AMD64/ARM-XScale/PPC-64 and other disassembler, full preview of MZ,NE,PE,ELF and other.
IMAVR is Atmel AVR 8-bit RISC chip emulator for UNIX. You can run your code before programming to chip. Embedded simple debugger and disassembler. Emulate wide range of AVR chip, wide range of their modules: EEPROM,USART, timers and so on.