When set to 'select similar' the Magic Wand tool should select all the same material / color in the scene.
When importing an OBJ you get a long list of meshes, it would be great if there was a selection mode to select all meshes with the same color / material so they can easily be put in a folder and be materialized.
A select connected function (double click on a mesh) would also be nice to select meshes that are next to each other.