Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
Google Sign-In is a secure authentication system that reduces the burden of login for users, by enabling them to sign in with their Google account.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Lodash is a JavaScript library which provides utility functions for common programming tasks using the functional programming paradigm.
Moment.js is a free and open-source JavaScript library that removes the need to use the native JavaScript Date object directly.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
A modest JavaScript framework for the HTML you already have.
Underscore.js is a JavaScript library which provides utility functions for common programming tasks. It is comparable to features provided by Prototype.js and the Ruby language, but opts for a functional programming design instead of extending object prototypes.