Friends Become Lovers, Romance/Shoujo

Childhood Friends
Childhood Love
Student-Student Relationship
Love Triangle
Friends Become Lovers

Childhood Friends, Childhood Love
Childhood Promise
Fat Male Lead
Kind Male Lead
Rich Male Lead
Sudden Confession
Appearance Changes
Student-Student Relationship
Friends Become Lovers

Adapted to Anime
Nerdy Female Lead
Smart Female Lead
Cold Female Lead
Awkward Female Lead
Delinquent Male Lead Strong Male Lead, Smart Male Lead
Simple-Minded Male Lead, Handsome Male Lead
Hot-Blooded Male Lead
Childlike Male Lead
Friendship
Ambitious Female Lead
Hard-Working Female Lead
Love Confession
Slow Romance
Opposites Attract
Love Triangle
Friends Become Lovers
Possessive Lover
Changed by Love
Clingy Lover
Couple Growth
The marriage happened in the end.

Childhood Friends
Neighbor-Neighbor Relationship
Rivalry
Rich Male Lead, Handsome Male Lead
Rich Female Lead, Beautiful Female Lead
Rivals Become Lovers
Secret Relationship
Reverse Harem
Possessive Lover

Arranged Marriage
Childhood Friends
Curse, Ghost
Cohabitation
Strong Female Lead
Rich Female Lead
Friends Become Lovers
And they have 4 children at the end of the story

Full Color Manhwa
Reincarnated in Another World
Reincarnated in a Book World
Reincarnated in the Past
Time Rewind
Second Chance
Kind Male Lead
Scary Male Lead
Loyal Male Lead
Strong Male Lead
Smart Female Lead
Contract Marriage
Friendship
Magic, Divine Powers
Friends Become Lovers

Adapted to Anime
Student-Student Relationship
Rivalry
Friendship
Slow Romance
Dense Male Lead
Popular Male Lead
Love Triangle
Persistent Female Lead
Tsundere Male Lead
Height Difference
Short Male Lead x Tall Female Lead
Friends Become Lovers
Comedy Couple
Couple Growth

Adapted to OVA
Student-Student Relationship
Awkward Female Lead
Shy Female Lead
Popular Male Lead, Polite Male Lead
Kind Male Lead
Friendship
Slow Romance
Opposites Attract
Height Difference
Tall Male Lead x Short Female Lead
Friends Become Lovers
Multiple Couples

Childhood Friends
Handsome Male Lead
Love Triangle
Friends Become Lovers
Older Female x Younger Male
Possessive Lover

Edo Period
Red-Light District
Secret Identity
Courtesan, Male Disguised as Female
Rivalry
Master-Disciple Relationship
Childhood Love
Childhood Trauma, Hidden Past
Emotionally Strong Female Lead
Handsome Male Lead
Strong Male Lead
Slow Romance
Reverse Harem
Older Male x Younger Female