Raindrops in Boast Busters
Raindrops is a jasmine Pegasus who shares her design with Derpy Hooves. She often appears as a background pony throughout the series.
Depiction in fan fiction
Raindrops is in the fan fiction The Lunaverse, an alternate universe where Raindrops and five other background ponies essentially become the main six, with Raindrops becoming Element of Honesty. Raindrops' personality in the fanfic can come across as stable and slightly dull. She's a member of Ponyville's weather patrol, and takes her job very seriously, though she also enjoys it thoroughly. Read the full character description of Raindrops in Lunaverse. Assuming that her personality is the same in the real universe, Raindrops is often serious and dull, but also a good honest reliable friend like Applejack. The lack of fanfiction involving Raindrops has led to much speculation surrounding her.
It has been suggested that Raindrops has some relationship with Derpy, most commonly as a sister or close friend, due to similar design and close proximity such as in Feeling Pinkie Keen where she and Derpy drop things on Twilight. This idea of a Derpy/Raindrops relationship is explored in the short fanfic "Raindrops and Cloudbubbles". In this alternative ending to the fanfic "Bubbles", Derpy meets Raindrops who takes Derpy to her house. Derpy's father had coincidentally gotten together with Raindrop's mother and they decided to move to Ponyville, where Derpy and Raindrops grow up together.