The Double-Bladed Scimitar can be found in Eberron: Rising from the Last War, page 21.
You gain a +1 bonus to attack and damage rolls made with this magic weapon. While the sword is on your person, you also gain a +1 bonus to saving throws.
If the sword is on your person, you can call on its luck (no action required) to reroll one attack roll, ability check, or saving throw you dislike. You must use the second roll. This property can't be used again until the next dawn.
The sword has 1d4 - 1 charges. While holding it, you can use an action to expend 1 charge and cast the wish spell from it. This property can't be used again until the next dawn. The sword loses this property if it has no charges.
If you attack with a double-bladed scimitar as part of the Attack action on your turn, you can use a bonus action immediately after to make a melee attack with it. This attack deals 1d4 slashing damage on a hit, instead of 2d4.
This weapon requires two hands to use. This property is relevant only when you attack with the weapon, not when you simply hold it.