Kotaro also counts, although he's capable of maturity when the situation calls for it.
Johji of Yu-Gi-Oh! — He is bratty and, of Yugi's party, the only one who he gets along with is Anzu... because he is a perverted baby who lusts after women
Yuuri of Mermaid Melody Pichi Pichi Pitch is a brat who continually insists that she isn't a child and stomps off to go do her own thing, always failing miserably. After she leaves the cast (for the most part), Seira is introduced on the good side; she does mature, and was only selfish because she had yet to gather the facets of love (which was the original intent of the quest for her to be born; having her heart stolen complicated things).
Naruto's prototype was even brattier and far more of a Jerk Ass. In order to take revenge on a boy who spread rumors about him, he trapped him in a hole, pretended to offer him a lift out, then urinated on him, leaving a stench that lasts 10 days.
Konohamaru, the Third Hokage's grandson, is a more straightforward example. Although later on, we see him Take A Level In Badass and give a Pain body a Rasengan.
Mannen in Pretear, the self-proclaimed leader of the younger half of the Leafe Knights. He tends to get the group in trouble by demanding to be treated as equals with the older knights, but he seems to genuinely mean well.
Also, Akaya of Rikkai. It's developed so far that Brat is basically his second name in fanfiction.
Anita King of RoD the TV, at least partially (especially prominent in the anime's early episodes).
Yahiko from Rurouni Kenshin is an interesting case. He's obviously the Bratty Half Pint, and is not only fully aware of it, but doesn't want to be. His character arc is his journey from Bratty Half Pint to full-fledged Shonen hero.
Ten from Urusei Yatsura. One translation of his full name, Jariten, literally means "Bratty Ten". His insistence on "Ten" is for much the same reason Sakuramboo, the ugly little Buddhist priest, usually calls himself "Cherry" — Sakuramboo can mean "Cherry" (as in the fruit — Sakura refers to Cherry Blossoms), but also "Deranged Priest".
Meilin from Cardcaptor Sakura. When she isn't fawning over Syaoran, she's constantly bragging about her abilities, real or imagined, and early on, whining whenever Sakura gets a card over Syaoran and just being a general nuisance. However, she is also very determined, caring, and always ready to take action, traits which become more prominent late into her appearance in the series.
Mashiro from the yonkoma (and its anime adaptation) Mikakunin de Shinkoukei. Self-important, and always trying to find a way to either take advantage of, or inconvenience her prospective sister-in-law Kobeni. Thankfully her bratty instances are curbed either by her own childish tendencies, or by Kobeni's older sister Benio, whose attentions Mashiro is terrified of.
The main character of Hakkenden Touhou Hakken Ibun, Inuzuka Shino, is this. Of course, he's Older Than He Looks due to possessing Murasame as the price for being his vessel and wielding his power is to have one's time frozen. Aka, he's actually 18 instead of 13. Him being a brat is semi-justified by Who Wants to Live Forever? and the issues that come from always being seen by others as a kid. And, unlike most Bratty Half Pints, he is actually probably one of the strongest characters.
In the first OVA series, Sasami of Tenchi Muyo! was this, her first appearance being spent playing a prank on Tenchi and insulting Ryoko. This held over into the first Pretty Sammy OVA, but once the second Tenchi Muyo! OVA series came out, she came out of this and became the more mature of the girls. The whole Tsunami thing probably helped with that.
In Umi Monogatari, Urin is childish and petulant at times, moreso to people on land than her mermaid sister Marin.
Miu from Ichigo Mashimaro. Rare is the episode where she doesn't earn Nobue's wrath, usually in the form of being knocked face-first into the floor.
Mai and Mami from Explorer Woman Ray, a couple of treasure-seeking teenage girls who steal an artifact from the title character left back in Japan, in the hope of meeting her and returning it.