It can be difficult finding great 3D models - even after finding just the right look you also need to make sure the technical specs (complexity, format, texture types) are all correct. See our 3D Model Formats article for more information.
Though we cannot guarantee 100% compatibility, here are a couple of links to 3D stock sites with the correct filters set to find models that will perform well in AR.
The filters set are: FBX format available, Real-time or low-poly models only, up to 100k polygons
If you want to know if a 3D model is the right format before purchasing, get in touch with the plattar support team and send us a link/file. We can’t promise a model is compatible, but we can tell you if it is definitely incompatible.
Generally speaking, 3D models that can be used in games are a good fit for your AR scenes.