Armwarmers. aka fingerless gloves aka 'texting gloves.' Add them to any black outfit for more blackness, which is always good, plus some drama, which is sometimes good.
These are long — long enough to go up over your elbow (opera-length, if you're fancy). Or wear them below your elbow and they'll scrunch up nicely. In deep black stretchy jersey. The finger, thumb and and arm hole each have neatly bound trim. Get them here.