MMB always recommends working with devices that have been certified by the Zigbee Alliance. You can view a list of those devices here.
Aside from this list, we are aware of other devices that have been developed against the Zigbee specifications but the device vendor ultimately decided not to complete the official certification/registration process. It's best to directly ask the vendor which Application Profile they have implemented, including details about the Clusters, Attributes, Commands, etc.