Field that can store a list

Is there any field that can store a Python list(not as a string)? If not, is there any way I can store a list inside a field without typecasting it to string or any other data type?

You can use a dict field for that. But instead of a list, you will get a JSON-dictionary. See Fields — trytond 5.3 documentation and Model — trytond 5.3 documentation for more information. You can also take a look at the product_attributes module how it can be implemented.

For now, we do not have such field. But it is a feature requested: Issue 7851: Add MultiSelection field - Tryton issue tracker

I will try to use Dict and see what happens