Out of Universe:
Snowdrop is a light blue pegasus filly who appears as the main character in the 2013 eponymous animation, Snowdrop by Silly Filly Studios in which she is depicted as blind. Because of the popularity of the animated video, the character has appeared in numerous fanworks. Snowdrop is blind. However, her great sense of hearing makes up for this. At school, she was often bullied because of her disability. She views both winter and the night as underappreciated. She created snowflakes by molding snow into what she considered to be stars. She lived prior to Princess Luna's transformation into Nightmare Moon. - mlpfanart.fandom.com

As a fellow disabled person, I adore Snowdrop enough to include her in my headcanons. She's not a major character in any way- especially not in the Next Gen, and a mere reoccurring character in my side series that's not even posted in order, The Tale of the Two Sisters. But I did draw her, and I do have ideas for her and what happened after the events of the animation, and I'm about to explain it.

In Universe:
It wasn't long before Snowdrop was given a room in Canterlot, as flying in Cloudsdale can be considered dangerous for somepony who can't see- and luckily, moving was always on her agenda for her own safety. Celestia was quick to see her potential and Luna's growing friendship with the filly could prove beneficial as Celestia was beginning to spend less and less time with her sister due to royal duties. She was one of the few ponies in Luna's court rather than Celestia's, and was designated as 'Lady Snowdrop' due to her higher stature gained from her closeness with the Princess. As time went by, she became Luna's closest confident and the pony she would talk to whenever she was feeling down...

However, even Snowdrop's company wasn't enough as Luna began to transform into Nightmare Moon. Of course, even Nightmare Moon still felt what Luna felt, and made sure to teleport Snowdrop to a safe distance before her confrontation with Celestia happened. By the time the battle was over, Celestia had to go find her and break the news that Luna had to be banished. After that day, Snowdrop's mood rapidly decreased and soon moved away from Canterlot into a small cottage near the Everfree Forest. Of course, she was a mere pony, and passed away from old age soon enough- and Luna was never able to say goodbye...
At least her cottage was found once more, and soon revitalized into a home for a new, young pegasus.