"Eren's mother Carla from Attack on Titan. This, combined with the FMA example, have led the fandom to nickname this trope the "Dead Mom Side Pony.""
"As a part of her post Time Skip Adrenaline Makeover, Anna Stephanie from Blue Comet SPT Layzner lets her hair down from its initial Tomboyish Ponytail and styles it like this. She's not exactly a mother, but at this point of the series she's shouldering lots of responsibilities as The Heart of La Résistance."
"In Fire Emblem Jugdral, Lewyn wears his hair this way in Generation 2. Fittingly, he's a stern Team Dad in that part of the game."
"Natsuhi Ushiromiya has a sort of high ponytail variant in Umineko: When They Cry. She is more stern than most examples but she does treasure her family."
"Button's Adventures: Button's Mother wears her mane like this."
"Nei'kalsa of Drowtales is shown with this, which serves to emphasize her role as a mother figure to Sarnel (who's actually her brother, and while their mother is apparently alive she's also out of the picture). Especially since Word of God clarifies that she's pregnant in that scene so will soon be a mother for real."
Airi Yūnami had this as her default hairstyle(In human form), and had been a mother figure to the human children captured by her unnamed alien species, it's also hinted that she was Aoi Yaegaki's biological mother.