Well, These are common themes in the Manga/anime/movies I've been watching/reading.
I'll give examples of each
Vikings: Vinland-COMPLETELY about vikings, then random mentions of Norse gods and Valhalla and Valkyries, oh, and Thor popping up everywhere
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Vampires: Vampire Hunter D, Vassalord, Krory from D. Grey-man and more.
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Vincents: Vincent Valentine, Vincent Volaju, and Random Vincents scattered throughout all the things I watch (heh, even in WoW, random corpse named Vincent)
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Eyepatches: I Swear, So many men with eyepatches, its kinda amazing
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The Mafia: Either the main characters are in it, they're the main villain, or they're of some significance in a chapter of almost everything I've seen/read. Hell, one of my favorite Mangas revolves Completely around it.
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