The upcoming release of Inkscape has a new feature that allows an artist to select objects that have the same properties as the currently selected object. For example, you could select an object that has a fill of blue. Then, using the new feature select all other objects in the drawing with a fill set to that same shade of blue:
The new feature is a menu choice under Edit > Select Same or as a Context menu if you right click on a selected object.
Also there are other choices available to select same, including: matching both Fill and Stroke, matching just stroke, matching stroke style, or matching on object type.