Sapphire dragonfly

A sapphire dragonfly was a large, blue dragonfly that could be found in northwest Faerûn, including Icewind Dale, the Sword Coast North, and the Savage Frontier.

History
In the late 15 century DR, a sapphire dragonfly found its way into the home of Edgin and Zia Darvis in Targos. While Edgin moved to kill or capture the insect, Zia opened a window to "let it go". After Zia's death at the hands of a Red Wizard, a sapphire dragonfly appeared above her pyre, and henceforth the insect would remind Edgin of his lost wife. Eleven years later, the sight of such a dragonfly would ultimately help him to move on from his grief when he realized that he had to let his wife go just as she had once let the dragonfly go.

Background
According to The Art and Making of Dungeons & Dragons: Honor Among Thieves, the sapphire dragonfly was the only creature in the Honor Among Thieves film that was not taken from existing Dungeons & Dragons sources. The sapphire dragonfly was used to represent the concept of letting go of the past. In the Realms, it is possible this is a deity's manifestation such as a favored animal.