Four years ago I wrote about selection sets in AutoCAD. All of these commands still work great but at that time the SELECTSIMILAR command was only available in AEC versions (Civil 3D, Architecture, etc.) of AutoCAD. I am happy to say that since version 2011 the command has been available in plain AutoCAD as well!
To control what properties are chosen when the SELECTSIMILAR command is executed, use the SELECTSIMILARMODE system variable. Leaving it set to 130 will work for most users which means, according to the help file, “objects of the same type are considered similar if they are on the same layer, and, for referenced objects, have the same name.”
I use the SELECTSIMILAR command on a daily basis. I’m glad it’s available in all AutoCAD products now.