Before we answer the question of what devices are capable of offering WDS/Wireless bridge, let's talk about what a wireless Bridge is in the first place:
A wireless bridge, also often referred to as WDS (Wireless Distribution System), basically creates a media link between two Access Points, similar to a direct Ethernet link. The speciality of the Wireless bridge is the fact, that one can use the Ethernet port of the Wireless connected Access Point to extend the network furthermore - as a reference, have a look at the below graphic (extracted from our Access points' user guide):
Taking a look at Access Point Y & X, this is the classic example of a wireless bridge - both Access Points are interconnected via a mesh system, and X extends the network via Ethernet cable, adding Client C into the network.
Now, let's answer the question regarding what Nebula APs are compatible with WDS:
Searching to build a Mesh-Network instead (Root-Repeater-Configuration)?