VaTexAtlas is the plugin for Unreal Engine 4 that makes texture atlases simpler to use with UMG system.
The plugin is designed to work with sprite sheet data exported from TexturePacker in JSON Array data format.
Current version: 1.0 RC 1 (7 August 2016)
Moreover, plugin is completely free and available under MIT open-source license. You can use it in commercial projects, you can modify anything, etc. In other words, you're in charge.
Check the VaTexAtlas Wiki to know more about the plugin and get usage examples!