If you're looking for manga similar to Fluttering Feelings, you might like these titles.
A story about teenagers at the end of their first decade, meeting various people and figuring out who they themselves are.
Influenced by two of their friends, a pair of female high school students, Natsu and Kumiko, begin playing the popular MMORPG "Apocalypse Online." When they log in for the first time, they find they've been given a rare item, a pair of "marriage rings," which gives the two of them special bonuses when they are near each other. But while their "relationship" is a funny quirk of the game to Natsu, Kumiko secretly longs for it to become a reality...
Two women finally met at the end of the runaway game. Fragments of their ordinary high school life, where they had to fight a lot of people, pass through their memories.
After a misplaced confession lands the letter of Touno Hitomi in the locker of Saijou Nagisa, both of them experience feelings of attraction towards each other.
The story of a friendship/journey of two teenage girls in their third years of high school - 'Dong-ah' who likes to simplify things and 'Hoo' who tends to overthink.