The H-Factor

Select Similar does just what it's name implies. Select and object just by clicking it. Then right-click and pick Select Similar from the ensuing popup menu. All objects of the same type and layer will be highlighted. If you pick a block, then only the same block will be highlighted. You can now do whatever you want with them: move – erase – copy.

To control the parameters considered when picking Select Similar, you can type in SELECTSIMILAR at the command prompt and then choose SE to get to the settings dialog box.