Top 20 NuGet portable Packages

PCL Extension provides a Lua implementation for .NET, Xamarin.iOS, Xamarin.Android. This makes it easier to create cross-platform .NET libraries and apps.
PCL Extension provides an input/output implementation for .NET, Xamarin.iOS, Xamarin.Android. This makes it easier to create cross-platform .NET libraries and apps.
Make WPF and WinForms settings portable by saving them in the application folder. Read more at https://www.codeproject.com/Articles/1238550/Making-Application-Settings-Portable.
.NET client for PhoneSpeak.API (Portable Class Library version.)
Simple Portable Database is a library that provides a convenient way to store tabular and binary data in a local directory. The library uses csv and binary files to enable a simple persistence mechanism for local applications.
A Xamarin Forms control to render the native video player on every platform.
Redbridge Xamarin Forms MVVM portable client SDK library for iOS
Easy-to-use licensing library for .NET Framework, Mono, .NET Core, and Xamarin products.
.net wrapper for BreweryDb API
Xamling Core for development the Xamling way
The Portable .NET Client for the OpenAmat initiative
The Portable WebDAV Library is a strongly typed, async WebDAV client library which is fully compliant to RFC 4918, RFC 4331 and "Additional WebDAV Collection Properties". It is implemented as .NETStandard 1.1 library in oder to be used on any platform supporting .NETStandard 1.1.
Extend is a set of .Net extension methods build as PCL or .Net40 DLL. Extend enhance the .Net framework by adding a bunch of methods to increase developer’s productivity.
TCP-based FTP server implementation
.NET file system for portable FTP server
Provides extensions to use KBCsv with types in System.Data. Online at https://github.com/kentcb/KBCsv.
Redbridge SDK portable client SDK library for iOS
Commands for the portable FTP server
Breeze.Sharp is a data management tool for smart client apps. It retrieves data from the server using a rich query language, manages the entity graph of application data, tracks changes, and performs updates of changed data to the server.
An extremely light-weight, easy to use .Net pub/sub library