Tomboyish Ponytail

Anime & Manga

 * Makoto, aka Sailor Jupiter, of Sailor Moon has a long ponytail, and she's the brawler in the group. Particularly in her earlier appearances, she also sometimes sported a Tomboyish Baseball Cap to match.

Visual Novels

 * Mion of Higurashi: When They Cry wears her hair in a long ponytail. Mion is boisterous, perverted, and usually exhibits little in terms of femininity. She calls herself an "old man" regularly and in one arc Keiichi decides against giving her a doll (and instead gives it to their more feminine, mutual friend Rena) because he deems her too boyish for one. In contrast, her more girly identical twin sister Shion wears her hair loose. Mion is actually a subversion. She's much more feminine than she pretends to be. Keiichi giving Rena the doll upset Mion so much she ended up sobbing to her sister, which unwittingly caused Shion to become a Serial Killer.

Western Animation

 * The Loud House: Lynn Loud Jr. has an absurdly messy and unkempt ponytail, and is the Passionate Sports Girl and roughhousing Ladette of the siblings. Ronnie Anne and Luan have these as well, though they are a lot neater and more well kept, while Ronnie Anne is plenty tomboyish, Luan is barely unfeminine enough to quality as a tomboy.
 * Amethyst in the Steven Universe episode "Beach Party" wears her hair in a ponytail, and, of the Crystal Gems, is the most tomboyish due to being a Boisterous Bruiser and also messy at times.
 * Bridgette and Eva of Total Drama. Bridgette is a surfer-girl, while Eva is a Passionate Sports Girl and Action Girl.