The birthdays of the members of Team Anglerfish are all dates for WWII battles:
Miho = Operation Lightfoot (Second Battle of El Alamein)
Saori = Operation Barbarossa (German Invasion of Russia)
Hana = Operation Wacht am Rhein (Battle of the Bulge)
Yukari = Operation Overlord (D-Day, Allied invasion of occupied France)
Mako = Operation Fall Weiss (Case White, German Invasion of Poland)
One of the posters in Yukari's room in episode 5 shows a male Wehrmacht tank commander (Captain Ernst von Bauer) in realistic art style. This particular image is from the manga Black Knight Story by Motofumi Kobayashi of Apocalypse Meow fame. Earlier, there's also a poster for his manga Happy Tiger.
From the same room, another poster can be seen, referring to the C82 doujin titled Panther Details by doujin circle EXCEL, which itself is a sequel of a parody of Black Knight Story, titled Shima-Kishi Monogatari.
Yukari's hasty alias "Sergeant Oddball" is a reference to the war movie Kelly's Heroes, which features the namesake character played by Donald Sutherland.
Subtly Lampshaded in-universe as, while Alice and Naomi yell for someone to apprehend Yukari, Kay immediately bursts out in laughter upon hearing it.
Later, there is an extended Shout-Out to that movie as Yukari climbs a bell tower to get a good sight of Pravda's positions. She doesn't sound the bell, though.
An entire scene from the movie is presented in episode 10 being watched by the Rabbit team. (Specifically, the part where Oddball's tank ambushes a Tiger tank (forgetting they still had a paint round loaded) and are saved from the retaliatory shot due to the narrow alley preventing the turret from turning enough.) It's also Foreshadowing.
In episode 12, Rabbit Team carries out a similar ambush on the enemy Elefant tank destroyer, though being a tank destroyer it has no turret, instead the hull hits the buildings on either side.
The St. Gloriana girls are seen with a pink Land Rover Series IIA, in the "Pink Panther" scheme used by the SAS in Oman.
A cover from Takeshi Nogami and Tamura Naoya's Moeyo Sensha Gakkou is seen on the wall of the tank café in episode 5. One of the freshman girls is seen reading a volume of this series back in episode 2. Anzu is also seen holding a copy while Hetzer Trolling Kuromorimine.
Episode 7 has brief shout outs to Generals Bernard Montgomery and Heinz Guderian. Yukari prefers the latter.
The team name (Wild Duck/Mallard) for the B1 bis. All the prewar French tanks are nicknamed 'ducks' in World of Tanks for their shape.
When Pravda asks Ōarai to surrender in episode 8, Momo yells "NUTS!", which was General McAuliffe's response when the Germans asked him to surrender during the siege of Bastogne.
Long before that, as Sodoko was (hopelessly) berating the rest of the team for "not following school regulations", Erwin confronts her, surprisingly, with a Bon Jovi line:
Erwin: It's my life. It's now or never...
The History Club makes numerous references to various historical battles, like Stalingrad.
The City Ships are modeled (mostly) after WWII aircraft carriers. OVA 3 shows several more, detailed in the Shown Their Work entry.
The "Kartoshka" cake pops (a popular Russian confectionery) served during Pravda and St. Gloriana's Spot of Teamight be a reference to the Fan Nickname of WoT developer Wargaming.Net.note Wargaming.Net is a Belorussian company based in Minsk, and in Slavic countries, Belorussians are even more strongly associated with potatoes than the Irish are in the Anglosphere.
The urban area in episode 11 and 12 has apartment units similar to those of Kadykchan, a Russian ghost town in the Susumansky District of Magadan Oblast. note Built by GULAG prisoners during the late stages of World War II, the city was home to coal miners, but by 2010, the lack of demand for coal led to the complete depopulation of the town. This is the official story, of course: some parties believe that the Siberian winter took its toll on the aging town, and survivors were evacuated by the Russian military.
Maho's personal Tiger in the final match has the same number (212) as Michael Wittmann's Tiger during the Battle of Villers-Bocage.
Miho's personal Tiger during the previous final tournament match is numbered 217, same as Otto Carius' Tiger.
Ankou Team's "Panzer 5" role call routine in OVA 6 is a wholesale rip of Dairanger's.
In OVA 1, one of the Rabbit Team girls wears a squid shaped hat. This is likely a shout out to Director Tsutomu Mizushima earlier series "Squid Girl.