Other (RE Tooling): open-source projects that exist because someone reverse engineered a closed product, sorted by GitHub stars.
Installer that sets up a Windows VM for reverse engineering and malware analysis
ESP32 hardware hacking tool that speaks I2C, SPI, UART, IR, RF and more protocols
RF and reverse engineering framework for signal detection, protocol discovery and attacks
Interactive tool to explore the Windows Text Services Framework (CTF) protocol
PowerShell module with reverse engineering utilities
Online x86-64 assembly editor, emulator and debugger
Interactive shell for Avast's JavaScript engine extracted via reverse engineering
Shell tools for data translation and manipulation during reverse engineering
Example using the undocumented Windows dark mode API in Win32 apps
Tool to decode digital RF signals for RF reverse engineering
USB-PD sniffer/injector/sink based on Google's Twinkie for protocol analysis
Bundle of RE tools for analyzing and modding the PS Vita OS
Collection of undocumented Windows API declarations
Flying-probe automation stack for agent-driven hardware target discovery and pin probing
Documentation of undocumented Windows ETW providers
Chocolatey packages for the FLARE-VM and Commando VM analysis environments
Toolkit for analysing and reverse engineering legacy COBOL code (flowcharts, CFGs)
Reverse-engineered source of the Huorong security sysdiag driver
Research on the inner workings of Windows components
Examples of using Microsoft's undocumented Warbird technology
Portable reverse engineering framework that runs without installation
Experiments with hidden WSL COM interfaces and LxBus IPC
Reverse engineering research and tools for Windows Event Streaming Protocols
Rust bindings for undocumented Windows native (ntdll) APIs
USB DFU client for reverse engineers
Fake JVM/JNI interface in C for porting JNI-heavy Android games to PS Vita