Made my first WoW addon! It looks at a spells and tells you the Damage per Mana, the DPS (assuming perfect cast time) and the DPS per Mana. Simple, but mine! :
Damage reduction | WoWWiki | Fandom
Damage reduction - Wowpedia - Your wiki guide to the World of Warcraft
Extended Character Stats - Addons - World of Warcraft - CurseForge
Wowhead's Mythic+ Damage Calculator for Trash and Boss Abilities in Shadowlands' Dungeons - Wowhead News