custom field slider

I understand you mean the Custom Fields add-on? If so then i am afraid it only allows to create the basic fields you listed.

I know that, but can you add this functionality to next release or provide a code so I can apply it?

We are planning some additional field types but right now i cannot tell when this feature will be ready and if it will include a slider field.

If you would like to have a totally custom field you would need to dig into the Forms API i am afraid https://wpadverts.com/documentation/forms-api/