Total Recommendations: 28
Both take place in a WWII setting (only in Strike Witches, it's more of an alternate universe) and have the similar "military with comedy" type of action and humor. The characters representing their respective countries are also fairly similar (cute and comical Lucchini from "Romagna" is like Italy; somewhat wild and fun with the need-for-speed Shirley from the "United States of Liberion" is like America; strict, serious, and follows-schedules- to-a-T Barkhorn from "Karlsland" is like Germany; etc.).
Both take place in a similar period of time in Japanese history. They both revolve around samurai and other fighters (some with magical powers) and the like, Amatsuki emphasizing more on the magical sense.
Both were made basically to get the viewer, watching the TV/computer/etc., up and exercising. Training with Hinako is of the ecchi genre, while the Spice and Wolf II Specials are not, but both give out practically the same message. A more appropriate title for the Spice and Wolf II Specials would probably be "Training with Holo."
Both are plotless slice-of-life series that focus on a group of friends and their random, funny, cute, and heart-warming adventures. Both are also very clean, innocent, and pure while still managing to be an entertaining and nice series. The only major difference is that Azumanga Daioh revolves around a group of girls, while Kimi to Boku. revolves around a group of boys.
Both are series based loosely on fighting (more so in Ikkitousen) with a main cast full of females. Both take ancient history (Japanese history in Sengoku Otome and Chinese history in Ikkitousen) and turn it into an ecchi-fest full of busty girls.
In both, the main protagonist is the offspring of a demon and a human, and has demon-like powers/qualities that make him practically invincible compared to the humans around him. Both involve the protagonists hunting down/slaying/fighting/etc. demons alone or with the help of the supporting cast.
Both explore the adventures of a unique, entertaining, and cute cast of characters, who are all animals, during a five minute time-slot.
The main characters in both (Hare and Guu, Misaki and Usui) have similar, if not the same comedic kind of relationship. Usui and Guu have a sort of blasé, calm, and unpredictable personality. Misaki and Hare have the more emotional, dramatic, loud, and tough sort of personality. Both are quite odd pairings, it seems, but they really get along with each other well in the end.
Both are not only mystery series, but also, they both have an arc that takes place on a ship, which during this time, a serial killer is on the loose.
Both involve the main character(s) investigating strange supernatural events and how to cure them/get rid of them/etc.
Both are definitely unique in their forms of comedy and animation. At first glance, they seem to be shows for kids, but are really quite mature (Panty&Stocking more so than Hare nochi Guu).
Both are harems involving a bishounen male lead and several girls with different personalities and traits. They both have the same sort of "ecchi romance" with darker undertones (including insanity, split personalities, unrequited love and for Yosuga no Sora, love between twins).
Both revolve around homunculus, alchemy, and immortals all while taking place in the early 1900s.
Both are vampire anime that show the darker, gruesome, and less-glamorous side to vampires.
Both are short, funny, and about a large cast of talking animals, all with their own unique personalities and quirks.
Both are sweet, slice-of-life, shoujo romance stories that involve a dumb, air-headed heroine and one of her love interests who does not like her at first.
Both are harem anime based off of visual novels. Both have a complex plot which has to do with forgotten pasts, one-sided romances, etc. They also both have beautiful animation and eufonius singing their opening theme.
Both are dark "girls-with-guns" series. They both also take place in a foreign country other than Japan (France in Noir and Italy in Gunslinger Girl).
Both have a younger, air-headed main female character who, through some strange events, ends up without a home. She is then taken in by an older girl who acts somewhat motherly towards her. Both anime also have an almost all female cast that is generally good at fighting.
Both are comedies with a mainly all female cast. There is a bit of a twist on one of the main characters in each; Pucchan in Gokujou Seitokai is a puppet and Mariya from MariaHolic is a crossdressing boy. There is also a little girl acting as the dorm mistress, and there are shoujo-ai undertones in each.
Both are somewhat more mature, but humorous stories about students studying at a college specializing in a certain field (agriculture in Moyashimon and music in Nodame Cantabile). The art styles are similar, and there are several quirky, but funny and likable characters in both.
Both are about a poor girl that has lost their mother and is attending an ultra fabulous and rich academy. Both also involve the main female lead joining a club full of the school's elite students.
Both are slice-of-life comedies with a mainly all female cast. Many of the characters and the art are similar. The humor in both is somewhat the same as well as the overall atmosphere.
Both are touching harems with a lot of cute and sweet girls and a male protagonist who has few memories of his childhood.
Both are shoujo anime with a lot of magic and super bright colors. They both have a silmilar art style and a love-triangle between the main girl character and the boys she likes.
Both are all about music and have slice-of-life undertones. They also have very similar characters, especially Yui and Nodame, who both have "air-headed" and somewhat "weird" or "funny" personalities.
Both have zombies and good amounts of gore, however, HOTD is mainly fanservice/ecchi based where Zombie-Loan is not.
Both are stories about young girls that act as assassins/bounty hunters. They both also take place in a foreign country other than Japan (Mexico and Italy).