You can't go wrong with 'Beauty and the Beast'. Belle and the Beast are enemies at first. The Beast is a fearsome creature who imprisons Belle's father, and Belle is defiant towards him. But as time passes, they start to understand each other more, and their relationship transforms into love. 'A Court of Thorns and Roses' by Sarah J. Maas also has an 'enemies to lovers' aspect. Feyre and Tamlin start off in a hostile situation, but love eventually develops between them as they face various challenges together.
A good example is 'Wuthering Heights' by Emily Bronte. Heathcliff and Catherine have a complex relationship that starts with a sort of enmity. Heathcliff is treated as an outsider by Catherine's family, and their different social standings create tension. However, they share a deep, passionate connection that evolves into a tortured love. Also, 'Red, White & Royal Blue' by Casey McQuiston features Alex and Henry who are from different worlds (America and Britain) and initially have a sort of rivalrous relationship which then blossoms into a beautiful romance.
One great 'enemies to lovers' fantasy novel is 'A Court of Thorns and Roses' by Sarah J. Maas. It has a great build - up of the relationship between Feyre and Rhysand. Another is 'The Cruel Prince' by Holly Black. The dynamic between Jude and Cardan is full of tension and eventual love. Also, 'Shadow and Bone' by Leigh Bardugo has some elements of this trope as well.
You could also check out 'Given'. Ritsuka and Mafuyu have some initial friction. Ritsuka is a bit cold towards Mafuyu at the start. But through their shared love for music, they grow closer and develop a deep, loving relationship.
One great 'enemies to lovers' romance novel is 'Pride and Prejudice' by Jane Austen. The initial animosity between Elizabeth Bennet and Mr. Darcy is palpable, with misunderstandings fueling their dislike. But as the story unfolds, they come to see each other's true natures and fall in love. Another is 'The Hating Game' by Sally Thorne. The two main characters are office rivals who constantly bicker and compete. However, beneath the surface, there's an underlying attraction that eventually blossoms into love.
Character development is a big part. The characters have to change their initial negative views of each other. In a good 'enemies to lovers' BL novel, you'll see how they gradually start to understand and care for one another. For instance, they might discover shared traumas or interests that bridge the gap between them.
Another good one is 'Wuthering Heights' by Emily Bronte. Heathcliff and Catherine have a complex relationship. They grow up together but are separated by class differences, which turns them into something like enemies at times. Their love is wild and passionate, and the story shows how their enmity and love are intertwined in a very dramatic way.
One popular trope is the 'forced proximity'. For example, they get stuck in an elevator or on a deserted island. This forces them to interact and see each other in a new light. Another is the 'secret admirer' where one of them secretly likes the other even while being enemies publicly. The 'betrayal reveal' is also common. Maybe one discovers that the other was wrongly accused of something, which changes their feelings. And of course, the 'slow - burn' where the transition from hatred to love is very gradual.
One great example is 'Attachments' by Rainbow Rowell. It has an online aspect where the main characters start as sort of enemies in a work - related online environment. Lincoln, the IT guy, has to monitor the employees' emails for inappropriate use. Beth and Jennifer are two employees who often send emails that Lincoln reads. At first, he seems like an enemy invading their privacy, but as he gets to know them through their emails, he falls in love with Beth. It's a really sweet story that shows how an online connection can transform from something negative to a romantic relationship.
Some excellent 'enemies to lovers' fictions are 'Cruel Prince' by Holly Black. Jude and Cardan are enemies in the faerie world. Jude is a mortal living among the faeries and Cardan is a cruel prince who bullies her. But over time, their relationship changes into something more passionate. 'The Cruel Prince' shows how power dynamics and initial hatred can transform into love. Also, in 'The Vampire Diaries' book series (although it has a TV adaptation too), Elena and Damon start off as enemies. Damon is a vampire who seems menacing to Elena at first, but as the story unfolds, they develop a deep and complex relationship that has elements of love despite their initial enmity.
The 'Shadow and Bone' trilogy by Leigh Bardugo has elements of enemies to lovers. Alina and the Darkling have a complex relationship. At first, Alina sees the Darkling as a powerful and somewhat menacing figure. But there's also an attraction between them. The Grishaverse setting, with its magic and different factions, makes their relationship journey even more interesting.
A good one is 'Devil in Winter' by Lisa Kleypas. Sebastian, Viscount St. Vincent, and Evie are sort of enemies in the beginning. Evie is in a difficult situation and Sebastian offers a rather self - serving solution which she initially resents. But as they are forced to be in each other's company, they grow closer and their relationship turns into a loving one. These novels are great because they show the development from animosity to love in a historical context, with all the social rules and expectations adding to the drama.