> Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions.
I am using it for https://letsblock.it, so that I can ensure the filter corpus is in the right license without requiring a CLA.
Breaks it down nicely.
There are all sorts of other licenses of course and if CC-0 doesn't meet your needs, talk with your lawyer because any restrictions you want to enforce will require lawyering up to enforce. There are no "gnu police" and MIT an BSD don't enforce the MIT and BSD licenses.
Good luck.
From what you've said, consider the "MIT" or "MIT No Attribution" (MIT-0) License.