Here is the list for most commonly used NodeJS packages list those are frequently used:
Express: A fast, unopinionated, minimalist web framework for Node. Express aims to provide small, robust tooling for HTTP servers, making it a great solution for single page applications, web sites, hybrids, or public HTTP APIs.
Request: A simplified HTTP request client. It supports HTTPS and follows redirects by default.
Socket.io: Socket.io makes WebSockets and real-time possible in all browsers and provides built-in multiplexing, horizontal scalability, automatic JSON encoding/decoding, and more.
Mongoose: A MongoDB object modeling tool designed to work in an asynchronous environment. It includes built-in type casting, validation, query building, business logic hooks and more, out of the box.
Browserify: Browserify will recursively analyze all the require() calls in your app in order to build a bundle you can serve up to the browser in a single script tag.
Bower: Bower is a package manager for the web. It works by fetching and installing packages from all over, taking care of hunting, finding, downloading, and saving the stuff you’re looking for.
Backbone: Backbone.js gives structure to web applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and connects it all to your existing API over a RESTful JSON interface.
Debug: Debug is a tiny node.js debugging utility modeled after node core’s debugging technique.
Forever: A simple CLI tool for ensuring that a given node script runs continuously (i.e. forever).
Gulp: is a streaming build system that helps you automate painful or time-consuming tasks in your development workflow.
Hapi: is a streaming build system that helps you automate painful or time-consuming tasks in your development workflow.
Http-server: is a simple, zero-configuration command-line HTTP server. It is powerful enough for production usage, but it’s simple and hackable enough to be used for testing, local development, and learning.
MongoDB: The official MongoDB driver for Node.js. It provides a high-level API on top of MongoDB-core that is meant for end users.
Nodemailer: This module enables e-mail sending from Node.js applications.
Passport: A simple, unobtrusive authentication middleware for Node.js. Passport uses the strategies to authenticate requests. Strategies can range from verifying username and password credentials or authentication using OAuth or OpenID.
Request: Request is Simplified HTTP request client make it possible to make HTTP calls. It supports HTTPS and follows redirects by default.
Socket.io: It’s a node.js real-time framework server.
Sails : API-driven framework for building realtime apps, using MVC conventions (based on Express and Socket.io)
Commander: The complete solution for node.js command-line interfaces.
Jade: Jade is a high-performance template engine.
Vue.js: Vue.js is a library for building interactive web interfaces. It provides data-reactive components with a simple and flexible API.
Restify: If you are looking to build a RESTful API, then Restify library will give you the quirks and tools required to perform the task.Restify is the library you will want to use when building REST services for the web.