pefile is a Python module to read and work with PE (Portable Executable) files

The FLARE team's open-source tool to identify capabilities in executable files.

Pester is the ubiquitous test and mock framework for PowerShell.

Windows kernel and user mode emulation.

An open-source user mode debugger for Windows. Optimized for reverse engineering and malware analysis.

Malware Sample Sources

oletools - python tools to analyze MS OLE2 files (Structured Storage, Compound File Binary Format) and MS Office documents, for malware analysis, forensics and debugging.

A collection of software installations scripts for Windows systems that allows you to easily setup and maintain a reverse engineering environment on a VM.

.NET debugger and assembly editor

Resources, tools about .net reverse engineering.

Reverse Engineer's Toolkit

sandbox approach for malware developers and red teamers to test payloads against detection mechanisms before deployment