Ability to somehow select materials independantly of objects to run batch operations on only the materials..

I need to batch rename some materials. The only way Edit > Batch Rename is able to interact with materials is if they are on an object in the scene.

You can set the outliner to the Blend File mode which shows a list of all Materials. In the context menu there is a Rename option. There should be a Batch Rename option there as well which interacts on the items (of any kind, materials in this case) that are currently selected in that outliner.