If you're looking for manga similar to Kimi ga Shinu made Koi wo Shitai, you might like these titles.
In an all-woman planet of intelligent fungi, Arriala and Erriela get married! But a member of the royal mushroom family is smitten with Erriela and is willing to start a war over her. To rescue her wife, can Arriala traverse the wild and treacherous mushroom kingdom and hope to survive?
Hoshigawa Kurumi has a crush her classmate, Nikaidou Nika, who sits in front of her in class. She's popular with guys, so she has no trouble going from boyfriend to boyfriend. One day, Nikaidou borrows an eraser from Hoshigawa.