Unity

Lightning fast pathfinding with heavily optimized algorithms and a large feature set.

Apex Path handles dynamic pathfinding including local avoidance steering and dynamic obstacles.

Crystal is a fast, scalable and extensible utility based AI framework for C# and Unity.

Augmented Reality SDK that includes libraries, utilities, and examples.

Scripts and prefabs to help with the development of Google Daydream and Cardboard apps for Android and iOS.

Scripts and Great examples to abstract the use of VR controller actions in Unity.

Virtual Reality framework that allows for powerful interactions, locomotion, and visual effects.

Augmented Reality SDK with image and object recognition, smart terrain and extended tracking features.

Provides camera, controllers, and other effects for use in FPS games.

A 2D controller that behaves very similarly to Unity's CharacterController component.

An easy to use Unity 3D library for creating illustrated Interactive Fiction games.

Strange is a super-lightweight and highly extensible Inversion-of-Control (IoC) framework, written specifically for C# and Unity.

Create maintainable games faster, better, more stable, and consistent than ever before.

A complete puzzle game with a clever twist. Play it online.

An input manager that tames makes handler cross-platform. controller input easy.

Bind game inputs to methods via code or using the inspector to add event driven input handling to your project.

Makes it easy to recognize gestures and other touch input.

Makes handling complex gesture interactions on any touch surface much easier.

A set of CSG level design tools for building complex levels quickly inside Unity.

Unity Ads is a video ad network with quick and seamless integration using regular and opt-in ads.

Build social and realtime games with an open-source distributed server.

Build networked games without having to know the details of networking or write any complex networking code.

Plug and play cloud networking that also works for local hosting. Free for up to 20 concurrent users.

A fast and simple way to save and load data on all major platforms supported by Unity.

A customizable dynamic day and night weather system that creates realistic storms and weather.

Provides a dashboard with metrics to help track active players, sessions, retention, and revenue.

Tips in gif form showing a few ways to use the editor more efficiently.

Gems of Unity Labs for user education.

Short videos showing some handy tips when using Unity.

Using the stencil buffer in Unity to draw splatter effects on surfaces. This could be used for paint or blood splatter.

This series of posts will introduce you to shader coding, and is oriented to developers with little to no knowledge about shaders.

An great collection of general purpose game programming content.

Tutorials designed for learning the C# scripting side of Unity.

A short tutorial about removing the small gaps that sometimes appear between adjacent sprites.

Lots of great game development patterns useful when making games with or without Unity.

A video tutorial providing an in-depth explanation of Unity's new UI system.

The official tutorials for scripting, animation, audio, and almost anything Unity related.

Beginner and mid-level tutorials focused on learning Unity features or creating small example games.

Official tutorials from Microsoft for creating Microsoft HoloLens applications.

Unity's official documentation on developing virtual reality applications.

Tween any numeric property or field (including Vectors, Rectangles, etc.), plus some non-numeric ones (like strings). This is the follow-up to HOTween.

An open source, lightweight tween library aimed at making tweening objects dead simple.

A simple, and easy to use animation system.

FOSS, and also the most lightweight tweening library for Unity. Allows you to tween any value you have access to via the .value() method.

A powerful UI system and event notification framework.

A alternative to render text in uGUI by using the distance field technique, which allows crisp fonts at any scale. This was recently purchased by Unity and will be integrated into the engine in the future.

In-game debug console that displays output from `Debug.Log`.

The new GitHub for Unity extension brings the GitHub workflow and more to Unity, providing support for large files with Git LFS and file locking.

Easily group objects together

Editor extension to bookmark and later recall scene views.

Makes it easy to manage positions of assets in the scene with easy to use snapping tools and many more features to improve the scene creation workflow.

Editor extension for merging scenes and prefabs, also integrates with VCS.

UniRx (Reactive Extensions for Unity) is a reimplementation of the .NET Reactive Extensions. Rx cures the "asynchronous blues" without async/await.

Collection of miscellaneous open source scripts and helpers for Unity 5.0.

Easily stream your Vimeo videos into Unity or record and publish out to Vimeo.

Quickly make gameplay prototypes, A.I. behaviors, animation graphs, interactive objects, and more using finite state machines.