Alternate titles: Useless Villain, Peripheral Villain. Have we got this one already? This is the Evil Counterpart to the Useless Protagonist. This is a villain who serves such little purpose to the story that if you took them out or replaced them with someone else, you'd never notice. This is not the same as a Harmless Villain, who cannot pose any adequate threat to the heroes, or a Designated Villain, who does leave an impact on the narrative, even if their actions aren't actually evil.
Hello, Unknown Troper. You'll need to get known to lend a hand here.