Pearl of Power

Wondrous item, uncommon (requires attunement by a spellcaster)

While this pearl is on your person, you can take a Magic action to regain one expended spell slot of level 3 or lower. Once you use the pearl, it can’t be used again until the next dawn.

Source: Dungeon Master’s Guide (2024) p. 284. Available in the SRD and the Free Rules (2024)