What are your favorite npm packages?

Let's share some of the most loved npm packages you use for the majority of projects. Consider both client and server-side. For me those would be:

Frontend - react, react-dom, react-router-dom, antd, styled-components, axios, moment, validator.
Backend - express, mongoose, CORS, body-parser, dotenv, uuid, nodemon, concurrently, morgan, ejs, helmet, bcrypt, jsonwebtoken, nodemailer.

What are some of your favorite npm packages?