PInvoke.BCrypt by: Andrew Arnott

P/Invoke methods for the Windows BCrypt.dll.

PCLStorage by: Daniel Plaisted

PCL Storage provides a consistent, portable set of local file IO APIs for .NET, Windows Phone, Windows Store, Xamarin.iOS, Xamarin.Android, and Silverlight. This makes it easier to create cross-platform .NET libraries and apps.

prometheus-net by: andrasm, qed-, lakario

.NET client for prometheus.io

PDFsharp by: empira Software GmbH

PDFsharp is the Open Source .NET library that easily creates and processes PDF documents on the fly from any .NET language. The same drawing routines can be used to create PDF documents, draw on the screen, or send output to any printer. This is the PDFsharp PDF Core package. See Project Information for details.

PInvoke.NCrypt by: Andrew Arnott

P/Invoke methods for the Windows NCrypt.dll.

Quartz by: Marko Lahma

Quartz Scheduling Framework for .NET

Pkcs11Interop by: Jaroslav Imrich

Managed .NET wrapper for unmanaged PKCS#11 libraries

PInvoke.Kernel32 by: Andrew Arnott

P/Invoke methods for the Windows Kernel32.dll.

Prism.Core by: Brian Lagunas, Dan Siegel

Prism is a fully open source version of the Prism guidance originally produced by Microsoft Patterns & Practices. Prism provides an implementation of a collection of design patterns that are helpful in writing well structured and maintainable XAML applications, including MVVM, dependency injection, commanding, event aggregation, and more. Prism's core functionality is a shared code base in a Portable Class Library targeting these platforms; WPF, and Xamarin Forms. Features that need to be platform specific are implemented in the respective libraries for the target platform.

Portable.ConcurrentDictionary by: Stef Heyenrath

This is a .NET Standard 1.0, .NET 2.0, .NET 3.5, Silverlight 5.0 and Windows Phone Silverlight 8.0 & 8.1 backport from System.Collections.Concurrent.ConcurrentDictionary as defined in .NET Core

Portable.BouncyCastle by: Claire Novotny

BouncyCastle portable version with support for .NET 4, .NET Standard 2.0

Plugin.FirebasePushNotification by: Rendy Del Rosario

Receive and handle firebase push notifications across Xamarin.iOS and Xamarin.Android

Plugin.CurrentActivity by: James Montemagno

Provides a simple solution for getting access to the current Activity of the application when developing a Plugin for Xamarin. This will lay down a base "application" class for developers in their Android application with boilerplate code to get them started.

PdfPig by: UglyToad

Reads text content from PDF documents and supports document creation. Apache 2.0 licensed.

Plugin.Permissions by: James Montemagno

Check to see if your users have granted or denied permissions for common permission groups on iOS and Android. Additionally, you can request permissions with a simple cross-platform async/awaitified API.

protobuf-net by: Marc Gravell

Provides simple access to fast and efficient "Protocol Buffers" serialization from .NET applications

Polly by: Michael Wolfenden, App vNext

Polly is a library that allows developers to express resilience and transient fault handling policies such as Retry, Circuit Breaker, Timeout, Bulkhead Isolation, and Fallback in a fluent and thread-safe manner.

QRCoder by: Raffael Herrmann, Shane Krueger

QRCoder is a simple library, written in C#.NET, which enables you to create QR codes.

PDFsharp-MigraDoc by: empira Software GmbH

MigraDoc Foundation - the Open Source .NET library that easily creates documents based on an object model with paragraphs, tables, styles, etc. and renders them into PDF or RTF. This is the MigraDoc PDF Core package. See Project Information for details.

PInvoke.Windows.Core by: Andrew Arnott

P/Invoke types for common Windows APIs.