It would appear that Mixamo has a new competitor in the auto-rigging game, accuRIG from Reallusion (makers of Character Creator and iClone). It is a free download, available for Windows only, that is completely free, although an account is required to download. You can then import your own 3D model in FBX and OBJ format and quickly create a character rig in just a few simple steps. Once completed the results can be downloaded as FBX, USD and in Reallusions own iClone format.
AccuRIG is described as:
AccuRIG is a free application designed for fast and easy character rigging, aiming to reduce production effort for character artists by focusing on model design with automation and simplicity. Achieve accurate and superior rigging results in 5 simple steps for models in A/T/scan poses, or with low/high/multiple meshes. Direct export to all major 3D tools, or upload directly to ActorCore and try tons of production-ready animations for game, film, archviz, digital twins and more.
ActorCore (Animations & Models)
You can learn more about accuRIG and see it in action in the video below.