Chance.js is a javascript library that can generate random numbers, characters, strings, names, addresses, dice, and pretty much anything else.
EasyTimer.js is a simple timer/chronometer/countdown library compatible with AMD and NodeJS.
EasyTimer.js released under the MIT license
Markvis is a plugin to generate charts in markdown with few lines of code.
Amplitude.js is a lightweight JavaScript library that allows you to control the design of your media controls in your webpage -- not the browser. No dependencies, Amplitude.js is available under the MIT License.
jQuery Tree plugin allows you to create tree structure using Bootstrap or Material Design styles. Free open source plugin distributed under MIT License.
Pit-scheduler is a jQuery plugin that lets you manage tasks through a complete interface. It's compatible with Bootstrap and available under the MIT license (free to use).
jQuery.datepicker is a futuristic datepicker plugin for web. It's customizable and API reference also available.
Muuri creates responsive, sortable, filterable and draggable grid layouts with lots of features in one library. Comparing to what's out there Muuri is a combination of Packery, Masonry, Isotope and jQuery UI sortable.
Notyf is a dead simple, responsive, vanilla javascript plugin to show notification.
Notyf is under MIT licence.