As present there is not an option to create list button with custom lightning component. But i think i have seen same think in some org. But not available any more. Is there any way we can create list button to add lightning component.
- Create vf page and add this page to list button and call lightning component using light out dependency.
- create a visual flow , add the url in list button and call the flow using URL.
But is there any OOTB functionality present.