Wand of the War Mage, +1, +2, or +3

From Dungeon Master's Guide, page 212. Found on Magic Item Tables F, G, and H.

Description
Wand, uncommon (+1), rare (+2), or very rare (+3) (requires attunement by a spellcaster)

While holding this wand, you gain a bonus to spell attack rolls determined by the wand's rarity. In addition, you ignore half cover when making a spell attack.