+250 Spell Damage For All Levels, Short Duration (Patreon)

The mob "Manawraith",

https://www.wowhead.com/npc=15648/manawraith

Located in the west of Eversong Woods sometimes gives you a buff called "Arcane Residue". This increases spell damage taken by 125 but also increases it by 250. These numbers are far too high: the damage has not been scaled down properly. For low-level casters this allows them to one-shot literally everything.

The buff lasts only two minutes.

The main applications for this buff would be for leveling and twinking pvp.