Ho-kago Comes Again by Color Hiyoko Aikoukai and Okeya K-ON! Doujin — Ongoing

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Spring by Okeya K-ON! Doujin released Dec 19 '17 Comedy Pocky game
Summer by Okeya K-ON! Doujin released Nov 23 '18 Body swap Comedy
Autumn by Okeya K-ON! Doujin released May 16 '21