This one came up today and I thought it was worth putting here as an answer
The user wanted to select all of the line objects in a project file that were unnamed. The tool to use is the Advanced Select tool, and select all the data you want to select from, then select the type of data e.g. Linestrings or Polylines or multiple data types and then select that have the following property “Name” and then use the option for equals a regular expression and then enter “.” this means any character as its first character (note an unnamed object will have no character at all) so we also check the checkbox to invert the selection - ie the tool first selects all named objects and then inverts the selection to select all of the unnamed objects. You can then relayer, rename, make a selection set, change the color etc. of the objects selected to get them where you need to be.
Alternatively you can use the RPS Name by Layer command which allows you to either set yup a mapping file that says all objects on Layer XXXX, name them ABCD and have an entry for each layer and that will rename the objects that only have no name. You can leave named objects alone. You can also just use the Layer Name to name the objects - i.e. if the object is on a layer called Fred then the object would be named Fred after running the process.
Video shows you how