Gish’s Aftermagic (5e Feat)

Prerequisites: the ability to cast a spell
You can use the residual magical energy of your spells in combat. You gain the following benefits:

When you cast a spell of 1st-level or higher that does damage, the next successful weapon attack you make as part of an Attack action before the end of your next turn deals an additional 1d10 damage, the from the same type as the spell cast.

After casting a spell from the abjuration school, you gain a number of temporary hit points equal to 1 per level of the spell slot spent.