The slow burn where they both love each other but think the other person doesn’t feel the same way but literally everyone in the world knows how they feel about each other.
They absolutely loathe each other but everyone around them knows that they actually totally love each other.
Royalty/Commoner ESPECIALLY when the commoner didn’t know they were royalty and feel so betrayed when they find out.
I mean really, any version of the Person A is hiding something about their identity for decentish reasons and Person B eventually finds out and is just so betrayed and Person A has some version of the “I didn’t mean for it to happen, but it did. I fell in love with you.” (Chasing Liberty is my favorite, okay?)
Also the “we’re from different worlds” version, too.
And of course Person A is trying to rescue/find/reunite with they significant other and Person B gets enlisted to help but then totally falls in love but thinks Person A really loves sigo, but when they finally are reunited they realize they really love Person B.
If arthur hadnt had been born literally everything would have turned out perfect. Ygraine wouldnt have died, Uther wouldn’t have declared war on magic, He would have been forced to claim Morgana as his own. She would have taked her place on the throne. Her parents wouldnt have died. Gauis would have been able to marry and have a life with Alice. Merlin would have grown up with his father in his life and would have married Freya. Lancelot and gwen would have married. Morgana wouldnt grow up resenting Uther for hating magic. Literally everything would have been perfect. And my small warlock child wouldnt have had to go through so much pain.