Tim Völcker’s OutlinerPlus for Maya which allows you easier access to filter the types of node shown, has recently updated to version 1.2 which added a node display for Maya 2013, as well as a node display for V-Ray and Maxwell Render.
Check out the OutlinerPlus for Maya, a replacement for the standard Maya outliner to speed up node selection and the general workflow here.
OutlinerPlus is meant to speed up the general workflow in Autodesk Maya by replacing the standard Maya Outliner. It can do everything the Maya Outliner can do but with OutlinerPlus you can easily display only the type of nodes you want to see. This speeds up the selection of nodes like textures, Maya materials, mental ray materials, animation curves as you don’t have to open the slow hypershade anymore to simply select such a node for example.
