How about a feat that works like lucky but for strength?
Feats of Strength
You are powerhouse among your people. Gain the following:
- Increase your Strength score by 1, to a maximum of 20.
- You gain a pool of three Feats of Strength points. You can spend these points to gain advantage on a Strength check, attack, or save, but you must choose to do so before the dice are rolled. This feat will counteract disadvantage from another source, but it will not trigger the rogues sneak attack damage. After a long rest, you regain your Feats of Strength points.
Thoughts?