Here are some ideas for when you want to write Enemies to Lovers but can't decide what they should be fighting about!
Fighting for a scholarship
Fighting for valedictorian
Fighting for top spot for a parking spot
Two schools focused on academics fighting it out for prestige or a scholarship or some kind of donation (computers, books, grant, etc.)
Debate team vs sports team
Football team vs Lacrosse Team -- right to use the field
Swim Team vs Dive Team -- Right to use pool
Cheer team vs football team -- both think the other is overrated
Hockey teams -- fighting between two schools
Football teams -- prank week before the big game goes wrong
Sibling is a member of the rival team
Dad is the coach of the rival team
New kid is really good and now I'm worried about losing my captain spot
One sided rivalry at the gym -- you're taking the machines I want on purpose/I don't know who you are
We're both going for a promotion
After a merger, we're both fighting to keep our job during downsizing
We're both fighting for the private corner office
We're both CEO's and are fighting to get a client
Uber private CEO and Journalist looking for a breakout story
Two laywers on opposite sides of a case
Two chefs fighting for a prize at a cooking combination
Two campaign managers fighting during a political race
Mob boss and police captain
Parole officer and convicted felon
You captured me and now I can't help notices how cute you look
You're the villain and I'm the hero who vowed to take you down
You killed my family and now you've kidnapped me
We're fighting in secret but you're also the person my friend is talking to but I also think you're cute
He's an asshole, she's a nerd
New to the group and threatening the present ecosystem
My siblings ex is now friends with my friends
Families are at war so we have to hate each other
S/he is next in line, s/he is the daughter/son to the family trying to take the crown
You planned an uprising and kidnapped me
Forced marriage that neither want and now there are tensions
Fighting for recently opened larger apartment upstairs
Roommates that can't live together
I didn't know I was getting a roommate and you are insulferable
Leader vs kidnapped rival
Ghost vs current tennate -- both want each other gone
Rival Supernatural Academies
Vampire Hunter vs Vampire
Shifter Hunter vs Shifter