Arcana domain

The Arcana domain was a deity domain that granted divine spellcasters like clerics with spells and powers related to arcane magic and lore.

Powers
The priest with this domain had proficiency or greater skill pertaining to matters of the arcane.

After the Spellplague, they treated certain divine prayers as arcane magic, namely lance of faith (for clerics), divine bolts (for invokers), radiant vengeance (for avengers), and virtuous strike (for paladins) and could aim arcane spells better afterward.

Spells
After the Second Sundering, clerics who chose this domain could learn two wizardly cantrips. They were granted free access to the spells detect magic and magic missile initially; then magic weapon, Nystul's magic aura, dispel magic, and magic circle at moderate experience; and arcane eye, Leomund's secret chest, planar binding, and teleportation circle at the highest levels of power.

Channel Divinity
After the Spellplague, they could channel divinity to use arcana ward, which shielded against elemental forces.

After the Second Sundering, they could instead use arcane abjuration to turn away otherworldly beings.