Avatar SDK contains a solution to generate rigged full-body avatars from images. You can find more details in our blog. This functionality is currently available in the Web API and the Avatar SDK Unity Cloud plugin, you can refer to the curl sample on how to reconstruct a full-body model in the FBX format or to this Unity sample scene.
Moreover, we provide an 'Avatar SDK for UMA' extension for the Avatar SDK Unity Cloud plugin. This extension allows for generating avatars compatible with the Unity Multipurpose Avatars (UMA 2) plugin. You can find more details here.
All these options are available on the Pro subscription plan or higher.