The Negamoon Family is the many villains from the Negamoon, a.k.a. Planet Nemesis, that invaded Earth, tried to attack Crystal Tokyo of the future, and take over Tokyo in the past. Its name implies that it may have been associated with the Negaverse.
The Negamoon Sisters, Emerald, and, at one point, Diamond send droids to achieve their goals.
The Negamoon Sisters, one by one, were turned good by Sailor Moon using Moon Crystal Healing Activation.
Rubeus was defeated by Sailor Moon, and was killed when he blew up his own ship in a vain attempt to destroy the Sailor Scouts.
Emerald was tricked into taking a crown from Wiseman, turning her into a dragon, and was destroyed by Sailor Moon's Moon Scepter Elimination.
Sapphire discovered that Wiseman was using them, and turned good and attempted to warn Diamond, but was killed by Wiseman.
Diamond also turned good, and sacrificed himself to save Sailor Moon from an attack by Wiseman, being impaled by it.
Wiseman was destroyed by Princess Serena and Princess Rini using their silver crystals (and help from the Sailor Scouts) to create an energy explosion.