Kaguya-sama wo Kataritai
4-koma spin-off of Kaguya-sama wa Kokurasetai.
The manga is about girls who worship the student council without knowing what really goes on in the council.
Extra chapters:
Vol. 1: K-agukoku!. Published in 31.05.2018 in Young Jump GOLD and made by the original author, it's a side-story to the main series. Summary: 4-koma that fills in events from previous chapters.
Ch. 28.5. Summary: Karen and Erika find a strand of hair in front of the council room.
Four bonus chapters published after the final one.