Top 20 NuGet WebApi Packages

Simple oppinionated abstraction on top of the Web API for SPA's
Entity Framework-based persistence layer for IdentityServer3
Extends Swashbuckle with OData v4 support! Supports both WebApi and OData controllers!
An implementation of HMAC for ASP.NET WebApi
Create WebApi from SQL Server Stored Procedures
CodeGenHero is an amazing Visual Studio extension that enhances developer productivity via code generation. This package should be added to projects that are the target of CodeGenHero templates creating WebApi controllers.
Swagger ISchemaFilter that uses FluentValidation validators instead System.ComponentModel based attributes.
Web API caching extensions
ASP.NET Web API formatter for partial response (fields) JSON output.
Extends Integration Service with the ability to simple host WebApi controllers.
Allows you to customize your swagger documentation using code, including support for providing multiple examples for responses and parameters.
Extensions and helper methods that make working with HttpClient easier as an API.
The files and references that are essential for a Breeze ASP.NET Web API 2.2 client and server on Entity Framework 6.
An implementation of HMAC for ASP.NET
KissLog AspNet WebApi package. Contains the components required to hook Asp.Net WebApi applications with KissLog. Install this package to Asp.Net WebApi applications.
The Area registration class template for HBD.Mef.Mvc When installed a new class named "ModuleRegister.cs" will be added. You should rename this class and update the Module name according to your module.
The Bootstrapper class template for HBD.Mef.Mvc When installed a new class named "Bootstrapper.cs" will be added in App_Start folder.
Adds HAL support to ASP.NET Core
HAL Models for producing HAL Json
ASP.NET Web API exception filter for logging errors to ELMAH. Ported from Fabian Vilers' Elmah.Contrib.Mvc.