V-Ray Extra Attributes are attributes that may be added to various object nodes in Maya to add additional V-Ray functionality to the object(s). Extra Attributes may be added to a node through the Attribute Editor's menu bar: Attributes > VRay when the object's node is currently selected.
Transform Attributes are specific to transform nodes in Maya to accomplish a variety of tasks allowing you to exempt or skip the object from rendering, assign the object an ID number, or assign the object a user-defined attribute.
