Method #1 : Template
This method requires you to save an existing list as Template
You can then include all the List Items in the Template:
Then (from Site Contents) create a new list from that saved template
As it includes All Items, You have to delete the unwanted items by hand
Method #2 : Clone item
Alternatively, by adding some JavaScript code to every ListItem (with a Calculated Column or Client-Side-Rendering) you can add a button to clone (copy/create) a ListItem to another List.
This SO answer:
Set default values in new controls on custom form
shows how to clone within One List; you have to add the code to reference another List when creating the Item