Basketball:
* Slam Dunk: A classic, following Hanamichi Sakuragi's journey from delinquent to basketball star. It has a slow-burn romance between Hanamichi and Haruko.
* Kuroko's Basketball: Focuses on the "phantom sixth man" Kuroko Tetsuya, who uses his unique skills to help his team win. There are several interesting romantic subplots.
* Real: A realistic look at wheelchair basketball. While the romance isn't the main focus, it plays a meaningful role in the characters' lives.
Volleyball:
* Haikyuu!!: A truly engaging series about a high school volleyball team. The focus is on teamwork, but it also features several romantic relationships.
* Cross Game: Features a young girl who joins the baseball team after her brother dies. The story is a mix of sports and romance.
Baseball:
* Diamond no Ace: A young pitcher named Eijun Sawamura strives to make his high school's team, and faces challenges along the way. It has a strong romance between Eijun and his childhood friend.
* Touch: A story about twin brothers who are both talented baseball players. It features a charming love triangle.
* Major: A story about the son of a legendary baseball player, following his own journey to become a professional. Romance is a major part of the story.
Soccer:
* Aoashi: A story about a talented young soccer player who gets a chance to play for a prestigious team. It features a budding romance between the main character and a girl on the team.
* Days: Focuses on the underdog soccer team of a high school and features a realistic portrayal of romance and friendship.
* Captain Tsubasa: A classic series about a young boy who dreams of becoming a professional soccer player. It also features romance elements.
Other Sports:
* Eyeshield 21: This American football manga features a shy protagonist who becomes a star running back. It has a light but heartwarming romance.
* Baby Steps: A story about a high school student who takes up tennis. It offers a grounded and relatable portrayal of the challenges of pursuing a sport while navigating school life and romance.
* Free! - Iwatobi Swim Club: Focuses on competitive swimming and features several romantic relationships.
Important Notes:
* These are just a few examples, and there are many other great sports manga with romance included.
* The level of romance varies significantly from series to series. Some focus on it more than others.
* The romance can be a major plot point or just a subplot.
I hope this helps you find the perfect manga to enjoy!