If you're using the same list in multiple tasks, you can store it in a central location and even extend it on an per-task basis. For this you can dynamically include the list from another task. Simply add the name of the other task, surrounded by percent characters, into the list.
Example:
my_negative_folder1
my_negative_folder2
%name_of_another_task%
Here this list receives the contents of the other task's list.
Note: It's not possible to daisy-chain this.