DoC558 Doubles Half
Here’s a large group drill that allows the coach to roam.  The drill also allows you to isolate certain areas or patterns in doubles; crosscourt returns, serve and volley, etc.  Start with two players on one side (one up to serve with the other player serving the next point).  Two other players are in the one up and one back or two back positions on the other side.  The extra players will be in a line ready to rotate in.  Points are started with a serve and players can only score when they are serving.  If the server wins he stays on that side, if the returning team wins players rotate a spot.  The server only has to defend his half of the court but can play to the doubles court.