The Filter command was introduced in AutoCAD R12 and was a valuable tool to build custom object select sets for your drawings. Then in AutoCAD 2000 the Qselect command came along and the Filter command faded from use. I use both but I believe the Filter command still takes the prize for being the best custom selection set builder of the two.
Starting the Filter command will present the following dialog box.
One feature that I believe makes this tool better than Qselect is the ability to save selection set criteria and then reuse it between drawings or later during another AutoCAD session. After composing your selection set criteria, enter a name in the "Save As" field and press "Save As" to retain your settings for future use. If you change your selection criteria and want to replace a saved setting just reenter the same name and "Save As" again.
The Filter command will allow you to compose searches using Boolean selection criteria. In the example below the Filter command will select all objects on layer "Walls" or find all blocks with the name of "Doors" when apply to the drawing.
One of my favorite features of the Filter command is the abiltiy to add the properties from a selected object then remove or edit any of the unwanted selection criteria before applying the filter. In the example below I have selected a text object in the drawing which lists all the properties in the composing window.
When you select Apply, you can use your selection window to search your complete drawing or any portion you desire. All objects that fit the selection criteria are highlighted and can be used at once with any editing command or later with the "Previous" option to any "Select Object" prompt.
The Filter command offers a complete selection filter list, shown above, at all times. Qselect only offers a filter list of currently used objects in the drawing. You can build custom filters as any time because of this feature.
The Filter command does not have an icon for execution on an Ribbon panel, it has fallen from grace. I encourage you to add one of your own to your custom Ribbon panel and re-discover a powerful command.