REDasm
The OpenSource Disassembler
REDasm is a cross-platform disassembler with a modern codebase useful from the hobbyist to the professional reverse engineer. All features are provided by LibREDasm which loads plugins developed in C, C++, and Python3 (you can also support new languages if you want!) and an user-friendly Qt frontend. You can hack and improve REDasm without any issues and limitations.