Proof that the remaining 10% is worth dying for here.
Since you have no interest in ordinary fanfics, here are some recommendations made by Tropers for Strike Witches fanfics, all of which have to be signed to stay on the page. Feel free to add a fanfic of your own to the list, but remember to use the template found here.
You can also add to the current recommendations if you want. Refrain from posting Conversation in the Main Page though; that goes in the discussion page.
Synopsis: Loosely based on Battle of Britain and set in 1940, this doujin follows Britannia Royal Air Force Ace pilot, Squadron Leader Constantia "Tia" Harvey, after surviving the Evacuation of Dunkirk after the Neuroi overtakes Gallia, Tia is assigned to lead the Foxtrot Foreign Volunteer Aerial Squadron composed of pilots from Britannia, Karlsland and Ostmark. The Foxtrot Squadron mission is to protect the South of London from the invading Neuroi. As Tia deals with her new subordinates who are either quiet, arrogant, proud or loners, she also has to deal with her guilt over losing her old squad-mates in Gallia including her best friend.
Comments: A excellent doujin loosely based on Battle of Britain. Many of the characters in this doujin are based on their movie counterparts and author ogitsune shown his work in the planes, battles and history during that era. The story is pretty good as well as it deals with Tia trying to get over the guilt of losing her old squad-mates while she leads a new squad of foreign pilots who's different personalities come into conflict with each other.
Synopsis: A shared world fan-fic based on the Gulf War. Set 40 years after the series, in August 1990, three Neuroi hives appeared above Arabian Peninsula. Soon the peninsula was occupied by the Neuroi. In response, the UN organized multinational Coalition forces. By March 1991, the Coalition forces were successful in reclaiming the Arabian Peninsula. Started as few character profiles drawn by Ogitsune, this series grew into a large scale shared world based on events of the Gulf War. The series consists of short stories, manga, character profiles, and settings created by various artists from Pixiv.
Comments: Yet another series started by Ogitsune, this time set in more modern setting. Much similar to the original series, many characters/events are reference to that of real life. This is more war/military oriented fan-fiction, including not only the story witches but also depiction of regular military, various weaponry, and operations. Since this is a shared work by various artists/authors, quality of contents is YMMV. But it's certainly interesting to see how different creators take on same series of events. Also, seeing witches with more modern equipment is very cool.
Strike Witches Quest,(NOTE: This is from the suptg.archive. Some images may be unsafe for work, and expect some foul language.) by planefag. Now has a Tropes Page.
Recommended by Sorrowman9000, HK-87
Summary: You are a pilot. After crash landing your P-61 Black Widow on the home of the 501st, Your asshole of a superior officer assigns you and your crew to be the U.S. Army Air Corps first liaisons to the Joint Fighter Wing. How will those with pants survive in the lair of the pantsless? How will you survive the possibly homicidal Sparkle-Bitches? And above all, how can we turn them into asshole pilots like us, while messing with them all the while?
Comments: If you like the idea of magical genderflipped aces fighting aliens in WWII, but don't want to feel a little dirty from watching so much fanservice, this is definitely for you. The quest runner, planefag, tries and succeeds at making Strike Witches less about cute girls groping each other, and more about what the life of a fighter pilot in the middle of a war is like. While an AU of the main SW universe, SWQ brings its own gritty, dark, and often hilarious views to a setting that most would consider little more than a glorified excuse for fanservice. To top this off, several people have written stories based inside of the SWQ continuity, and dear god are they awesome.
HK-87: Take Strike Witches, cut out 99% of the fanservice and most of the magical girl tropes, and replace them with Top Gun, Ace Combat and a dash of The War of the Worlds. Now add a main character who reads like Wizanon (See 'A Wizard Is You' on the Touhou recs page) traded in his spellbook for aviators and a P-61, and you get a Strike Witches fanfic that even people who hate Strike Witches might like.
Summary: You are a Naval aviator, flying the F-14B Tomcat in a US Navy integrated witch/pilot squadron. After you successfully land a damaged Tomcat, your CO springs his news to you: He's got to give you your dream shot. He's sending you up against the best. You and your RIO are going to Top Gun.
Comments: Another quest, set about forty-odd years after Strike Witches Quest, in the same universe, inspired by Ogitsune's genderflipped drawings of the Top Gun cast. The story starts out as Strike Witches meets Top Gun, before expanding into a World War III Cold War gone hot scenario, and is an excellent read. Also, the main character is less of an asshole compared to SWQ's protagonist.
Pairings: Only Sanya/Eila, but many other one-directional attractions are implied.
Summary: Eila finally confessed to Sanya, and Sanya accepted. Now the two are exploring the physical side of attraction. Only problem is, in the heat of passion Sanya loses control of her special abilities and is unwittingly broadcasting the details of her intimate encounter to every witch on the base. Now the entirety of the 501st is sleep-deprived and trying to confront their own subconscious desires.
Comments: Minna's subconscious wants a "witch harem", which is still not as funny as Gertrud's failed attempt at Thinking Unsexy Thoughts. The awkwardness that pervades the witches after Sanya and Eila's fateful night is absolutely priceless.
Summary: The 501st Joint Fighter wing ends up getting sent to the Call of Duty reality when an encounter with a Human Form Neuroi by Eila and Sanya prompt them to a hive after Eila receives horrific visions. Now trying to fight in a world embroiled in Modern, Human on Human warfare they must survive the third world war. During their missions with the COD protagonists in the hunt for Makarov, they discover the Mad dog Russian has bigger goals in mind, and ultimately fates of both the COD and Witches worlds are changed forever. But then the truth into the Neuroi and their goals are slowly revealed, much to the horrors of all.
Comments: A dark and yet compelling story that delves into the girls adjustment to human warfare and clues of the Neuroi's true nature is ominously hinted at. Some lighter elements come from the romance of the members of the main cast while the darker elements of the story converge. Some OC's both witch and COD verse created by the author and a fellow fanfic writer make appearances and supplement the main cast very well. Some of the characters are inspired from the Muv Luv series but re-imagined as either COD Military Personnel or Witches.