Top 20 NuGet webapi Packages

An async pattern for reading and setting ETag headers in ASP.NET Web API.
An Web API package that simplifies route localization of attribute routes.
A web api controller fluent mocking utility
Progressive Download Library for WebApi 2
A scaffold for building an application with Zurb for Applications and .Net
A simple HAL formatter for ASP.NET Web API.
Marvin.HttpCache is a complete implementation of the RFC2616 Http Caching standard for use with HttpClient, for all .NET Framework platforms (Windows Store, Windows Phone, WPF, WinForms, Console apps). Make sure to check the project site for the current status and to learn how to get started.
IdentityServer3 - Cache.Redis is a library that includes the implementation for client, scope, and user stores using Redis as distribuited cache system.
Enables WebApi projects to generate their RAML specification.
Web Api HAL Hypermedia Formatter
A Plugin for OwinFriendlyExceptions to handle WebApi2
JSend.WebApi extends ASP.NET Web API 2's ApiController and provides several helper methods to easily build JSend formatted responses.
RESTful Json WebApi client
Simple log4net appender which logs to the raygun.io API from your WebApi application.
A library bringing output caching (similar to MVC's "OutputCache"), to Web API actions. CacheOutput will take care of server side caching and set the appropriate client side (response) headers for you. This is a version for Web Api 2 only.
Allows you to organize your API Controllers in different ASP.NET MVC areas handling controllers with the same name in different areas / namespaces.
The udp-forwarder is an open source library for Web APIs. It grabs http requests sent to the API, creates a rich log event in a JSON format and sends it to a remote log service, like Logstash, via UDP.
A simple template for a setup class for WebApi projects. The intention is that all site setup and config is managed through classes dervived from this (apart from the generation of the IDependencyResolver) which would be used both to configure the HttpConfiguration object from GlobalConfiguration.Co...
Bailey.Web.Http provides a Windsor-based controller activator, a dependency resolver, and a dependency scope class for ASP.NET WebApi.
Use PocketContainer to resolve dependencies for ASP.NET Web API.