Amtrak.js - Amtrak.js is a super simple and easy way to interact with the Amtrak's train tracking API in both Node.js and the browser.

EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.

Immutable.js - Immutable persistent data collections for Javascript which increase efficiency and simplicity. - immutable-js/immutable-js

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

HeyForm - Paperless data collection with better data insights

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.