https://wiki.esoui.com/Events#Combat
EVENT_COMBAT_EVENT
But be warned: Not all events return a value or a unitTag so you are maybe not able to determine if you, and who you have hit with what value.
Define yourself a callback function for the event and check if it returns e.g. the dmg you have done to some enemy NPC/player.
Be sure to also register event filters so the event will not fire for EACH non-wanted stuff!!!
https://wiki.esoui.com/AddFilterForEvent