x64dbg is a 64-bit assembler-level debugger for Windows. The corresponding 32-bit debugger is called x32dbg.




Ghidra is described as 'Software reverse engineering (SRE) framework created and maintained by the National Security Agency Research Directorate. This framework includes a suite of full-featured, high-end software analysis tools that enable users to analyze compiled code on a variety of' and is a Decompiler in the development category. There are more than 10 alternatives to Ghidra for a variety of platforms, including Windows, Linux, Mac, BSD and Haiku apps. The best Ghidra alternative is x64dbg, which is both free and Open Source. Other great apps like Ghidra are IDA, GNU Project Debugger, OllyDbg and Cutter.
x64dbg is a 64-bit assembler-level debugger for Windows. The corresponding 32-bit debugger is called x32dbg.




IDA delivers robust disassembly and decompilation, supporting diverse processors and file formats. Its high-quality pseudocode mirrors original source code, aiding analysis of multi-platform software. It features dynamic debugging, metadata control with Lumina, and effective code deobfuscation.






GNU Project Debugger, or gdb, is a command-line, source-level debugger for programs that were written in C, C++, D, Objective-C, Fortran, Java, Pascal, assembly, Modula-2, or Ada and compiled for any of a number of different target architectures including x86, x86-64, IA-64...
OllyDbg is a 32-bit assembler level analysing debugger. Emphasis on binary code analysis makes it particularly useful in cases where source is unavailable.


Cutter goal is to be an advanced FREE and open-source reverse-engineering platform while keeping the user experience at mind. Cutter is created by reverse engineers for reverse engineers.



Rizin is a feature rich reverse engineering framework in development, focusing on stability and high code quality, a welcoming and curious community culture and implementation of cutting edge binary analysis research.




Radare, the highly featured reverse engineering framework. NOTE: it is better to use the "radare 2", not the "radare".
Features
Multi-architecture and multi-platform GNU/Linux, Android, *BSD, OSX, iPhoneOS, Windows{32,64} and Solaris i808.
Radare project started as a forensics tool, a scriptable commandline hexadecimal editor able to open disk files, but later support for analyzing binaries, disassembling code, debugging programs, attaching to remote gdb servers, ...




Okteta is a simple editor for the raw data of files. This type of program is also called hex editor or binary editor. The data is displayed in the traditional view with two columns: one with the numeric values and one with the assigned characters.

Hopper is a reverse engineering tool for OS X and Linux, that lets you disassemble, and decompile your 32/64bits Intel Mac, Linux, Windows and iOS executables!








Malcat is a feature-rich hexadecimal editor / disassembler / decompiler for reverse engineers and malware analysts. It has support for many file formats and CPUs, can scan for signatures, decrypt/decompress data, diff files and run python scripts.




IDA basically just the expensive professional version of Ghidra - Ghidra is FOSS, while IDA is free for specific use cases. If you want to get into decompilation, just start with Ghidra until you need a feature of IDA.