Still relevant

ember-auto-import

Zero config import from npm packages

ember-concurrency

Improved concurrency/async primitives for Ember

ember-truth-helpers

Ember HBS Helpers for {{if}} & {{unless}}: not, and, or, eq & is-array

ember-compoosable-helpers

Ember HBS Helpers for composing lots of things like functions, arrays, objects

ember-modifier

Make your own modifiers

fractal-page-object

Best PageObject utility I know

Outdated (unused)

ember-co

A tj/co implementation for Ember

ember-data-storefront

Predictable data-loading APIs for Ember Data

ember-cli-page-object

The ember-cli-page-object addon makes it easy to create page objects for your acceptance and integration tests

ember-responsive

Easy responsive layouts with Ember

ember-exex: Exceptional Exceptions for ambitious applications

Ember Exceptional Exceptions: Customizable error classes and error re-throwing with original error included

ember-elsewhere

Render elsewhere in the DOM, with nice composition, animation, etc. Based on 100% public API.

ember-keyboard

An Ember.js addon for the painless support of keyboard events.

ember-confirmed

An Ember asynchronous confirmation addon