Caroline Forbes - The Vampire Diaries
Since becoming a vampire, Caroline has gone out of her way and thrown herself into plenty of potentially fatal situations for her best friends and boyfriends. To protect them, with no end goal for herself. She purely loves them that much.
Trish Walker - Marvel's Jessica Jones
Trish tried her best to protect her best friend from Kilgrave and the dangers the world posed had they found out about Jessica's abilities. She learned to fight, to take care of herself, so she could take care of Jessica for once and the distraction of protecting her wouldn't be Jess' responsibility.
Caitlin Snow - The Flash
It's definitely Caitlin's fault. She cares too much to be part of a superhero team that continuously is tricked by those closest to them, that later turn out to be their greatesst enemy. Nonetheless, she always sees the best in everyone, even after all of the tragedy she's been through.
Maura Isles - Rizzoli & Isles
Her relationship with Jane has always been a strange, but thrilling one. Jane always runs into danger, whereas Maura is slow and cautious, warning her best friend of the dangers that could possibly hurt her. Even when it comes to footwear.
Karen Kim - Mistresses
Karen is the Mrs. George from Mean Girls of the Mom Friends. She's not like a regular mom, she's a cool mom. She's also the kind of slutty mom. She's comfortable with her sexuality, no matter how many of her friends settle down, and she'll always deal out her best therapist advice to her loved ones.
Lady Lola - Reign
Lady Lola literally sacrificed her life for her best friend, Mary, Queen of Scots. Even though the mission was a fraud, Lola believed Mary had asked her to murder Elizabeth, Scotland's rival. She sacrificed her life for her son, her best friend, and her entire country.