David Turnbull's Your First Meteor Application is a highly focused, beginner-friendly introduction to Meteor. David updates the book regularly when Meteor changes, so it's worth checking back every so often to look for new content.
The OData Server (GitHub: gizur/odataserver, License: MIT, npm: odataserver) by Jonas Colmsjö is an OData server that's backed by MySQL. It's easy to drop into an Express project, and it's designed to work as a quick "mobile backend as a service" type of app.
It has a simple HTTP API, and Jonas has included usage examples for curl that show you how to create users, databases, and insert data. It actually does things like MySQL database and schema creation, so it requires a MySQL administrator account to work correctly.
If you're interested in this and want to quickly try it out, the advanced usage guide has instructions for deploying it to Docker.
PWS Tabs (GitHub: alexchizhovcom/pwstabs, License: MIT) by Alex Chizhov is a jQuery plugin that helps you create modern, flat tabs, with CSS3 animations and Font Awesome Icons.
It uses data- attributes to set the tab's title and icon. The $(selector).pwstabs method accepts options for the tab position (horizontal or vertical) and the animation effect name.
The plugin source itself is fairly leightweight, and it comes with examples that include CSS. When I reviewed this plugin I had to download the examples because I couldn't access Alex's site, but he does link to a live demo in the readme.
wheelnav.js (GitHub: softwaretailoring/wheelnav) by Gábor Berkesi is an SVG-based library that you can use for a centerpiece animated navigation component. This might work well for a marketing website, which is the example Gábor uses, but I think it would be really cool on a child-friendly site with lots of bright colours site as well.
Mask.js (GitHub: bguzmanrio/maskjs, License: GPL) by Borja Guzmán is a library for validating input fields against dates, numbers, and text. It allows people to type in dates using numbers so they don't have to type in the necessary punctuation.
It prevents invalid input from being typed and allows you to skip between numbers, so it's less rigid than some implementations.
It comes with a command-line script that you can run with sloc file.js, and it'll automatically recurse directories. There are options for ignoring files (--exclude pattern) and selecting an output format (--format [json|csv|cli-table]).
Sloc has a Node module, so you can require('sloc') and run sloc(source, language) to get an object with various statistics. The project itself is well-tested, and has some cool usages like atom-sloc.
You can attach listeners with $.breakpoint.on, and an array is accepted so you can respond to different preset device sizes. There's also $.breakpoint.off for removing listeners, and $.breakpoint.changeBreakpoints for changing the globally recognised device sizes.
The project's documentation uses these techniques, but take a look at the demo for a more basic example to get started.
underscore-tpl (GitHub: creynders / underscore-tpl, License: MIT) by Camille Reynders allows you to expand placeholders stored within objects:
It can use mustache-style tags instead of ERB, and accepts the same options as _.templateSettings.
I've found myself using this type of thing for generating seed data or fixtures in tests, but I imagine it might also be useful if you're passing plain objects around with data-binding libraries as well.