This category unifies less common types of TLS certificates or certificates for other purposes.
DigiCert is authorized to issue certificates for Online Sign-Up (OSU) servers called Wi-Fi certificates. Wi-Fi certificates (for hotspots and servers) help to increase the trust of these networks and especially the security of their visitors.
Direct/FBCA certificates have use in the US healthcare sector because local regulation requires communication using this specific type of certificate.
Device certificates are designed for Internet of Things (IoT) and automation. They provide authentication and encryption for these devices. Every IoT device can obtain its own certificate which clearly identifies itself.