Auspicious Warning 2014

1st-level enchantment

Casting time: 1 reaction, which you take when an ally makes an attack roll, ability check, or saving throw
Range: 30 feet
Components: V
Duration: instantaneous
Classes: Bard, Sorcerer, Wizard

Just in time, you call out a fortunate warning to a creature within range. The target rolls a d4 and adds the number rolled to an attack roll, ability check, or saving throw that it has just made and uses the new result for determining success or failure.

Source: Deep Magic for 5th Edition (Kobold Press) · License: OPEN GAME LICENSE Version 1.0a details