x64dbg
An open-source x64/x32 debugger for windows
An open-source binary debugger for Windows, aimed at malware analysis and reverse engineering of executables you do not have the source code for. There are many features available and a comprehensive plugin system to add your own. Fully customizable color scheme. Dynamically recognize modules and strings. Import reconstructor integrated (Scylla). Fast disassembler (Zydis).