Filk Song: As noted on the main page, a number of IOSYS' songs can be thought of as being in the parody-filk style (credit goes to the Touhou Wiki):note For the sake of not having to worry about YouTube videos breaking at a later date, no links to the examples will be provided. Go look them up yourselves.
"Alienation" = "Shame" by Shuuchishin
"Autumn's Soldiers — Aki Sisters" = "DANZEN! Futari wa Precure" from Pretty Cure
"Saint Marisa's Gift" = "Rudolph the Red-Nosed Reindeer"
"Satosatorirasatosatorirasatorira Daibakuhatsu" = "Yuriyurarararayuruyuri Daijiken" from Yuru-Yuri
"Screaming Cool Match" = "Zetsubou Billy" from Death Note
"Song for the Cruelty of the Hell of the 60 Year Flowers of Sin" = "Saintly Girl Territory" from Rozen Maiden
"There Are No Bombs" = "There Are No Umbrellas" by Yousei Inoue
"The Traveling Emotions of Love At A Moon-viewing Hot Spring" = "Usagi" (a Japanese children's song)note This one seems like kind of a stretch; however, because it is listed on the Touhou Wiki, it's listed here
"The Ultimate Yakiniku Restaurant! Orin's Hell Mansion!" = "Love Dial 6700" by Finger Fivenote Partial parody; listen to the first 30 or so seconds of "Love Dial 6700" and compare