Normally a shield bash counts as an [improvised weapon](https://a5e.tools/rules/weapons) which does 1d4 (+ Str bonus) bludgeoning damage. If using shield spikes, this becomes piercing damage. You may throw a light shield, treating it as an improvised weapon that deals 1d6 (+ Dex bonus) bludgeoning damage. You can learn to be proficient with shield attacks, which adds your [[Proficiency Bonus]] to your attack rolls. This requires use of the Train activity, as if learning a [[00-Balance Of Powers/3-Mechanics/7-Adventuring/Between Adventures/Train#Weapon (or Shield Attacks)|new weapon]]. This proficiency covers both shield bashes and when you throw a light shield or buckler.