Unity Bluetooth Library for Android
The library allows you to control the Bluetooth capabilities of Android devices from the Unity3d Game Engine. It features a simple yet powerful API, giving you full control over connections with multiple devices simultaneously.
It is designed in a way that does not interfere with other extensions or plugins. The library is currently free and available on GitHub. You can also find it on the Unity Asset Store.
Originally created for microcontroller enthusiasts, the library now also makes it possible to build multiplayer Bluetooth games.
On the Asset Store, the package includes two extensions, each of which could be offered as a standalone asset on the Assetstore. The one I recommend is the BT Library, which provides all the essential features. The other extension requires less coding knowledge and offers a simple UI for configuration, but comes with fewer capabilities.
Note: Currently, I do not provide support for this library.