Total Recommendations: 36
Both are about schools for monsters. Rosario+Vampire is an ecchi/comedy/action/shounen anime, while Monster High is a comedy/shoujo anime based off an American tv series. R+V is made for teens while Monster High is directed at kids, but if you're into anime with cute monster girls then you may like both.
Both of these hentai are about girls brought into a mansion and made to become slaves. They both have a lot of BDSM and are very hardcore with fetishes taken to the extreme. Bondage Game revolves around several girls, while Pigeon Blood is mostly about the one main girl. Pigeon Blood is very masochistic, while Bondage Game, though it does have some masochistic scenarios, is more involved around very extreme, and sometimes downright disturbing fetishes.
Both are related to demons, Heaven and Hell, and bringing out the dark side in someone.
Both contain the two main women, who are both very busty in both series', being made into slaves. The sexual assaulter in Aku no Onna is a man, while in Kaizoku Sara it's mostly done by two younger girls.
Both contain the two main women, who are both very busty in both series', being made into slaves by younger girls.
Both are hentais containing one or more girls being trained into becoming slaves by a royal family. Both contain monster rape, humiliation, and magic, though Himekishi Lilia revolves around magic more and uses it to a further extent when it comes to the sexual scenes.
Both are made by the same people, so they both have similar art and characters, and both have a teacher teaching at a delinquent school. Rin x Sen is mostly about the teachers while Wanna is mostly about the students. The school in Wanna looks very similar, if not exactly the same as the one in Rin x Sen, and since it's made by the same people, I think it may actually be meant to be the same school.
Both animes are based in a historical (or in SnK's case, a historical-like) setting. They are both quite graphic, and both have a very similar look in terms of the setting (eg. the look of the cities, how they're both surrounded by walls, etc...). Both have a group of characters fighting their enemies, though AgK has a bit more of a medieval look overall. They also both contain shocking (frequently graphic) scenes that are often completely unexpected.
As soon as I started watching Mirai Nikki, I noticed a big similarity to Deadman Wonderland. In both series there's a strange girl that will do anything to protect the boy, both have everyone playing a life or death "game" where you either kill or be killed, the characters are very similar, and in both the main girl is yandere.
Hanamaru Youchien and Kodomo no Jikan are both about a young girl having a crush on her teacher. Kodomo no Jikan takes it to a more mature level, including ecchi scenes, and the 'crush' factor is more being fully in love, but they're both very similar in storyline and characters.
Both are horror, monster/tentacle hentais containing a little gore. They both have similar looking scenery, a similar story and ending.
Both dark, both hardcore, both involving lots of slaves. Both contain lots of fetishes and bondage, and if you liked one, then the other is a must-see.
Both hentais that have quite a lot of guro and are very hardcore. The characters are well animated, and the animes themselves are very detailed, so you'll need to have a strong stomach to watch either of these. The music is very similar too. Plus, they're both by the same company so you get the same sort of vibe from them both.
Both animes are romance comedies about a main girl and guy that have somewhat of a relationship together, and then another girl (Ayame is Asu no Yoichi, Tsugumi in Kannagi) that are in love with the main guy. Plus, both contain Haruka Tomatsu and Kana Hanazawa.
Both ecchi animes with cute girls, and a seemingly sweet storyline that starts to turn somewhat dark.
Both ecchi animes about two girls going after the same guy--one girl having a flat chest, the other one having big breasts, although Goshuushou-sama Ninomiya-kun they have that down to a much more realistic size. The characters are overall quite similar, just with different attitudes. Plus, Kiriko looks surprizingly similar to Iori except without glasses.
Similar slice of life/school/harem type stories, both containing similar characters in similar situations, and the school looks pretty much exactly the same in both of them.
Both are loli ecchis with cute long-haired girls. There's really not much more to say, except that if you're a fan of one you'll probably like the other too. Plus, the main character in both (Rin-Kodomo no Jikan, Yui-Koharu Biyori) are played by Eri Kitamura.
Both are funny mecha animes about a cute girl with pink hair that has a sidekick friend that they always hang out with. The characters are similar, and so are the drawing styles, in particular the eyes, which look very similar to each other iin both animes.
Similar characters, similar storyline, similar style. Both animes have similar aspects in one way or another. They both have a sort of "love-trangle" type story, and have a slightly horror-ish vibe to them with eerie scenes. Both seemignly sweet animes, then slowly getting darker and more emotional as the story goes on. You can really feel the characters emotions throughout the animes, and it's very easy to imagine yourself in their shoes. They can make you feel happy, sad, angry, and just about any other mixture of emotions, so you'll never really know what to expect with how you'll feel after you've watched them.
Both are cute, magical animes about a young girl, and they both seem to get a new outfit almost every episode.
Both of the animes are magical, and the characters are drawn in similar styles, in particular the eyes. They also both have a somewhat yuri-ish feel to them at some parts. Plus, they both have really cute outfits!
Both Tokyo Mew Mew and Princess Tutu are very similar in the way that they both have magical girls that have unknown identities. Ichigo is like Ahiru because they both are clumsy and get very nervous around the person they like, and both try to protect that person, and also try to keep their true identities hidden.
They both have a lot of action and similar types of magic, and they both are drawn in very similar styles. There's a lot of other little details that make them similar, and it was the first show I thought of while watching it.
Both are ecchi animes that have similar characters and are set at a mystical school. ZnT is set at a magic school, RV at a monster one. Plus, in both animes, the main girl has pink hair, and the main boys in both are similar. They both have Rie Kugimiya too!
Both of these animes are ecchis and quite similar in many ways, but Girls Bravo is particularly similar to this one eppy of ZnT because in eppy 12 of Girls Bravo (the first eppy of Girls Bravo second season) a giant octopus attacks the girls, just like in this OVA.
Both are ecchi, contain magic, and in a mystical setting. The characters are similar too. Also, in both the animes the main girl has pink hair and the main boy has blue hair.
They're both horrors that both have relations with living life more than once, and they both have their funny moments too that softens the horror a little bit.
Both are ecchis about a girl and boy that pretty much fall in love from the start, as apposed to the story going along and they slowly get more and more connected. Haruka is similar to Moka is RV by how they act very sweetly, softly and are both very popular in their school for being very pretty. Also, they both react similarly when they think someone is taking away who they love. In RV Capu2, Kokoa looks similar to Mika in NHNH, too.
They both have a sad aura to them, have interesting "camera" angles, and are very artistic, yet somewhat simple. The second season of EF (a Tale of Melodies) is also similar to She and Her Cat, but it reminded me of the first season more ^^
They both have similar types of violence and magic, and occasional slightly scary sequences that in both animes gives off the same sort of vibe.
Both animes are very ecchi and have similar situations going on. The characters are kinda similar too, and some are drawn in similar styles. The op songs are kinda similar too. If you liked one, you'll most likely like the other.
Similar storylines. Both main characters are very cute, very caring, and have a little animal "sidekick" that has much information about what is being collected. Both Sakura and Sumomo adapt to the idea of having magical powers and having to search for the magical items in similar ways. In CCS they are collecting Clow Cards, in ND they are collecting Stardrops. ^O^ Sakura and Sumomo kinda look alike too. ^^
In both animes a girl and boy live together in the same house, and both girls act tough. Also, in both animes there is a kinda mean girl character that tries to win the boy's heart infront of the girl he lives with. Both cute and funny animes ^O^