Azumanga Daioh is about the lives of a bunch of high school girls. The manga is serialized in Dengeki Daioh, a Shōnen magazine.
Also serialized in Dengeki Daioh is Yotsuba&! and Ichigo Mashimaro. Both are about cute little girls; both are also shonen series.
K-On! is clearly for a male audience, but appears to have garnered an extensive female fanbase in its wake as well. Point in case: it's airing on the Japanese Disney Channel, but edited of course.
While the manga has its fair share if Les Yay / Ship Teasing, Kyoto Animation toned it down for the anime and added more character focus (Except for Ritsu), presumably in trying to expand the audience. And based on its huge success, it seems to have worked, although it's not that girls dislike yuriper se—especially not in Japan.
In some countries they removed the fanservice and marketed it as a shonen show.
They still left all the cases of child abuse by the villains though.
Even though it's a Magical Girl series it's very heavy on the sci-fi and seems more like a Gundam series. Later installments take away the Magical Girl elements making it much more obviously aimed at men.
In one of his omake, Kano talks about how a little girl came up to him at Jump Festa with her mother and told him she loved Pretty Face and got his autograph.
Strike Witches might seem to be for girls judging from the cast, but any of the promotional art should make it clear, from the skimpy outfits and aerial combat, that it is filled with Fanservice all the way through.
When you first hear that Kiss Players is about Transformers powering up by getting a kiss from a human girl, you might think that the series is aimed at young girls. But then when you see the blatant, unrelentingsexual imagery, you think different.
Inverted for Lil Pri, while it is for girls, it is also for a more open market then just young girls due to Telecom'sPastProductions.
Chi's Sweet Home is about a cute little kitty cat and it's in a... Seinen manga magazine.
Tantei Opera Milky Holmes, while slapsticky, was aiming for the otaku audience from the start. Some of the things Twenty does are a big enough giveaway.
Amuri in Star Ocean
Bamboo Blade It's about a group of high school girls who are in their school's kendo club. And the manga is serialized in a... Seinen manga magazine.
A Little Snow Fairy Sugar is an extremely cutesy show about a young girl who hangs out with cute little fairies who create the weather. It aired at Otaku O'Clock and the manga adaptation was shonen. This is a very odd example, noting that the show itself is very G-rated.
Wandering Son is a calm, watercolor-like Slice of Life centered around twelve year olds going through junior high. Despite all this it's a Seinen, and it shows with its content matter.
Bokura No Hentai has a very cute style and one of the protagonists is very much The Cutie.. But it's a rather dark Seinen series.
Girl Friends focuses a lot on fashion, cosmetics, and other typically girly things, giving people the impression that it's a Shoujo manga. Even the fact that it's a Girls Love series doesn't prevent this, since Girls Love is popular amongst females too so people just assume that it's meant for a LGBT conscious young adult audience considering how realistically it handles the issues of a budding sexuality. Thus, people tend to be surprised when they discover that it ran in Comic High, a Seinen magazine.
Comics
Barbara Slate's Angel Love comic book series of the 1980s, having rather cute cartoonish artwork, yet dealing with serious topics such as drug abuse, abortion, critical illnesses, and incest.
There's a video of a five-year-old girl singing the "voulez-vous coucher avec moi ce soir?" line from Labelle's "Lady Marmalade." Presumably the train of thought was "It's about dancing, right? Girls love dancing!" Too bad it's not about dancing, it's about a prostitute, and the line translates to "do you want to sleep with me tonight?"
The Spice Girls. It's hard to tell exactly how much of their "Girl Power" theme was serious, and how much was self-parody, but it their lyrics make it clear that it was at least about sexual liberation... to the dismay of the parents of the 8 year olds who would parrot the lyrics.
Kids Rock changed the line in Wannabe from "If you wannabe my lover" to "If you wannabe my brother"; it is unknown how much the rest of the lyrics are modified, but if it's not at all, it adds whole new dimensions of creepy to the song. (it's unknown because the chorus was all that was heard on the advertisement)
Video Games
Touhou. A cast of characters that's almost entirely female, lots of fun songs (like this one), and lots of pretty colors. The games also have a cast consisting of various Youkai with some rather frightening powers, as well as claims of eating humans. And since the majority of the game's popularity comes from fan works on the Internet, unsuspecting girls are that much more likely to run into Rule 34. (They could just play the games, but then again, there's a reason they're calledBullet Hell...)
TheIdolmaster. A cute game about pop stars! With catchy songs, cute dresses and tons of accessories to dress up. But the target audience is otaku, with overpriced DLC no young girl could afford. Worth noting though is that Bandai-Namco is trying to get more girls to play the games, by adding male characters. But the original demographic complained!
Harvest Moon was aimed at a gender-neutral audience originally but you wouldn't know it by its mainly female fandom. The first few games had male-only protagonists but eventually they added girls, either in a Game-Favored Gender manner or in their own Distaff Counterpart's. Modern games always have an option to chose your gender. Recent incarnations of the game have began to look a lot more Bishoujo than before.
Lollipop Chainsaw. Despite the fact that it has "Chainsaw" in the title, has a clear M-rating on the cover, and the cover also shows that the main character will be having the disembodied head of her boyfriend hanging from her thigh, clueless parents might still think it's fine for their young daughter to play, just because it's about a cute cheerleader who kills zombies. Here's some of the content the game has: Zombies being chopped and cut apart by a chainsaw (although it's not as violent as most zombie games), lots and lots of swearing (one boss even attacks by yelling swear words which become physical and fly at you), dialogue involving sex, penises, erections, and naked pole-dancing, and a Game Over screen that shows the main character becoming a zombie and coming out of her grave, while her boyfriend says in an upset tone that he wishes he could've saved or protected her.
Word Of God claims it's meant to be more Feminist vs. meant for little girls... But, Furry Fandom being what it is, it's no shock that the majority of the audience is still teen-to-college-age guys.
minus is a brightly-colored cute-looking webcomic about an omnipotent little girl, albeit with a ton of Fridge Horror, but if TV Tropes is anything to go by, most of the people who read the comic are men.
McCracken's college assignment that spawned the series, Whoopass Stew (the title alone should make it clear which demographic he wasn't shooting for), went as follows. Girls beat the crap out of the Ganggreen Gang. Amoeba Boys rob a bank. Girls try to stop them but get stuck in their bodies. Girls prevail by flying to the sun, which kills the Amoeba Boys in seconds. Yeah. Not exactly tote bag-friendly icons, huh?
Speaking of Magical Girl, by sheer irony, Toei Animation (the creators of 'Sailor Moon'') remade the series as "Powerpuff Girls Z", a actual retelling of the series with a magical girl theme.
The Bratz dolls are more kid friendly, the TV show is definitely intended for their original target audience, teens and preteens. Among other things, the show actually has an episode where the girls investigate to see if Burdine murdered her last intern.
Making Fiends is actually a relatively dark cartoon about attempting murder with demons, and the colors are anything but bright, pastel or pink. But the two main characters are young girls. The original web animation was for a neutral demographic, but the daughter of a Nickelodeon producer loved it, and so Nick made a deal with Amy Winfrey to turn it into a cartoon. If you look at any of the message boards for Making Fiends, you'll see that male fans are extremely rare, though the show has gotten positive reviews from many male critics.
Considering Nickelodeon only aired six episodes of the show back in 2008, it could just be that people in general, male and female, haven't had a chance to see it.