Marayna

From Memory Alpha, the free Star Trek reference

Marayna was a holographic person created by Harry Kim. When the USS Voyager encountered an inversion nebula, Marayna began to appear outside the holodeck (having transfered herself into sickbay and stolen the mobile emitter), taking an interest in Tuvok.

Tuvok discovered that someone inside the nebula had interfaced with the holodeck and assumed the identity of Marayna. He transported into the nebula and found a lonely humanoid who maintained the energy of the nebula for her people. She demanded that Tuvok stay with her or she would attack Voyager, but eventually consented to let him go when Tuvok reminded her that he had a wife back on his homeworld, and whatever reason he remained for her would not be the one she wanted. He suggested she call for her replacement and return to her homeworld where she'll find someone more suitable. (VOY: "Alter Ego")

Maranya was played by actress Sandra Nelson. Her species and origin were not identified.

The costume from her appearance as an alien was sold off on the It's A Wrap! sale and auction on eBay. [1]