Shield Master

4th Level Feat, Shield Training

Repeatable: No   You’ve trained to use shields not just for protection, but also for offense, granting you the following benefits:   Ability Score Increase. Increase your Strength score by 1, to a maximum of 20.
Shield Bash. If you attack a creature within 5 feet of you as part of the Attack Action and hit with a Melee Weapon, you can immediately bash the target with your Shield if it’s equipped, forcing the target to make a Strength Saving Throw against a DC equal to 8 + your Strength modifier + your Proficiency Bonus. On a failed save, you knock the target Prone or push it 5 feet away. You can use this benefit only once on each of your turns.
Interpose Shield. If you are subjected to an effect that allows you to make a Dexterity Saving Throw to take only half damage, you can use your Reaction to take no damage if you succeed on the Saving Throw and are wielding a Shield, interposing your shield between yourself and the source of the effect.