Top 20 NuGet Packages

Based on http://www.nuget.org/packages/SAML2/, this removes dependencies on System.Web. Packages SAML2.AspNet and Owin.Security.Saml will implement SAML in those environments
Use the excellent BEMCheckBox in Xamarin iOS applications. BEMCheckBox allows you to create beautiful, highly customizable, animated checkboxs for iOS.
Porting of Windows Forms Screen helper for Windows Presentation Foundation (WPF). It avoids dependencies on Windows Forms libraries when developing in WPF.
SDL2# - C# Wrapper for SDL2
.NET libraries for automatically switching between HTTP and HTTPS protocols.
Custom DSC Resources for installing and uninstalling software packages and updates
Install Selenium.WebDriver.PhantomJS into your Unit Test Project. "phantomjs.exe" is copied to bin folder from package folder when the build process. / The MSBuild script that contained this package is free and unencumbered software released into the public domain. / "phantomjs.exe...
.Net SDK form 7zip, source original from http://www.7-zip.org/sdk.html, also in https://github.com/chrishaly/SevenZip
It wraps 7z.dll or any compatible one and makes use of LZMA SDK.
Stop copying and pasting code in order to support Async/Await! Shaolinq.AsyncRewriter generates async methods from your sync methods using Roslyn. AsyncRewriter is used extensively by the Shaolinq ORM/LINQ project.
An easy to use CFG/INI configuration library for .NET.
SharpShell is a framework that lets you build Windows Shell Extensions using the .NET Framework.
SharpZipLib for Portable Class Library (.Net 4.5, WP 8.0, WP 8.1, WinStore 8.1, MonoDroid, MonoTouch (Classic), Xamarin.iOS)
A strict, fast and mostly lock-free Software Transactional Memory (STM) for .NET
Client-side tools for the .NET Foundation Sign Service
SimMetrics is a Similarity Metric Library, e.g. from edit distance's (Levenshtein, Gotoh, Jaro etc) to other metrics, (e.g Soundex, Chapman). Work provided by UK Sheffield University funded by (AKT) an IRC sponsored by EPSRC, grant number GR/N15764/01. http://www.dcs.shef.ac.uk/~sam/simmetrics.html
Simple cryptography library that wraps complex hashing algorithms such as PBKDF2 for quick and simple usage.
Simple and straightforward library for TCP client and servers. Extremely useful for reading/writing with line-by-line command interfaces. Supports binary and string messages, automatic string trimming, and end-of-message delimiter (newline by default).
Easily Create Awesome Slideover's in Xamarin.Forms
Smocks is a library for mocking the normally unmockable. It can mock static and non-virtual methods and properties, amongst others.