UVRPN originated from the need to add a very thin layer in between an OptiTrack system and Unity to drive a PowerWall. The system is as of now (2018) rather incomplete but supports enough fidelity to be somewhat useful. You are invited to join the project and contribute.
SSTT Bounce is a simple AR Browser, literally. It uses a WebKit based browser and adds fast AR NFT tracking to it. Rendering is done by using three.js. Beside that, Bounce can be also used as an authoring environment, it automatically detects changes in the file structure and reloads files accordingly. This allows for some nifty "in-place" editing.
Beware, its not optimized to say the least, nor otherwise safe to use. It will eat little kittens for breakfast. If you are still not scared, give it a go.
SSTT - (Simplified Spatial Target Tracker) is a computer vision based tracking library for Augmented and Mixed Reality applications. SSTT aims to be used for novel interaction methods in AR and therefore prioritizes robustness over speed. It is a versatile toolbox of vision based tracking modules for desktop and embedded systems such as mobile phones. It implements numerous model based approaches from traditional markers, ID based frames, rectangular textured targets, natural feature targets and object recognition with online learning.
osgART is a cross platform toolkit for developing AR applications with the OpenSceneGraph API. osgART was invented by Julian Looser and then made by Raphael Grasset and Hartmut Seichter into a robust software framework with hundreds of useful features. The current working version is 2.x and is available from the osgART Website. osgART is been used in hundreds if not thousands of AR applications in research, education and commercial applications. It is most likely the most used open source AR application framework.