Insightfulness

10% increased maximum Energy Shield
16% increased maximum Mana
10% reduced Mana Cost of Skills while on Full Energy Shield [1]

Insightfulness is a notable passive skill that grants increased maximum energy shield, increased maximum mana, reduced mana cost of skills while on full energy shield.

Anointment

Blight anointment to unlock the passive:

Oil #1	Oil #2	Oil #3	Outcome
Verdant Oil	Verdant Oil	Golden Oil	Insightfulness	10% increased maximum Energy Shield 16% increased maximum Mana 10% reduced Mana Cost of Skills while on Full Energy Shield

Version	Changes
3.16.0	Make clusters more unique compared to each other as well as having a more clear identity. Remove niche or unneeded stats entirely, or shift them to Masteries. Improve many notables that have had secondary stats removed. No longer grants +10 to Intelligence. [Undocumented This change was not documented by any official sources. It was discovered through player testing or datamining.]
3.11.0	Many passive skill clusters offered the same thing as other clusters, with the only differences being the location on the tree and the number of passive skills in the cluster. We also wanted to reduce the power of some clusters that were overly efficient, and increase the power of clusters that were inefficient. [Undocumented This change was not documented by any official sources. It was discovered through player testing or datamining.]^[1] Now grants 16% increased maximum Mana (up from 10%).
3.7.0	Introduced to the game

↑ Bex_GGG (June 17, 2020). "All Notables and Keystones in Path of Exile: Harvest". Official Path of Exile forums. Retrieved November 3, 2021.