Not a big fan of these shows or their fanfictions (mostly out of how ridiculous they are), however I do enjoy some of it casually.
However one fanfiction of Kantai Collection that I enjoyed very much was a rather unique fanfic called Kancolle: Exodus Initiative, a sadly incomplete fanfiction where the main character is a Soviet battlecruiser of experimental nature, The Stalingrad, the first ship of the Stalingrad Class Project 82 battlecruisers*. The Abyssals take over most of the world and rule in collaboration with the countries of the world, but there are groups of shipgirls and people who are fighting back in a revek struggle). The fic begins in a bit of a confusing way (intentionally mirroring the chaos of the situation) but eventually clarifies a bit more. One of the interesting aspects is how they address Shipgirls. They physically embody their ships, so removing and replacing ribs and taping together organs or losing arms is treated as normal for them. Another unique part that reflects a bit of the Kancolle movie, is that they retain the memories of war that their soldier's and crew fought in. A unique aspect of the main character is that, the Soviet Navy, whose forces were often stuck fighting on land, since the Germans did not seek to engage in direct naval confrontation and tried to lock them in port with mines and nets, thus Stalingrad (the shipgirl) retains vivid and horrendous memories of the war. Her soviet perspective and ideology is also an influence and interesting aspect. (SPOILERS) Her mannerisms and ideology are initially treated with jocular quality, but it becomes a bit of a plot point in the last chapters. Part of this is seen with her hidden split personality 'Koba', who enunciates her position and is more dangerously and direct
(SPOILERS). I think this is so appealing to me because my Great-grandfather fought in the war and my own appreciation of the USSR.
TL;DR: I liked the commie ship and the way it was done
Original fic: https://www.fanfiction.net/s/11720694/13/Kancolle-Exodus-Initiative
Russian Translation: https://ficbook.net/readfic/9269278/24003647#part_content
*These ships are insane compared to any other battlecruiser and their internal systems honestly would be a good study for future warships and the range on the experimental guns was impressive.
- Cannons http://archive.is/rLmz