Malory Towers/YMMV

"[after jealousy over Jane putting Mirabel's games practice above doing chores for her Angela tells Jane to] "...go and find Violet Hill and send her to me. She can do my jobs instead of you." Jane was horrified at this outburst. She had given her heart to the beautiful, radiant Angela and now it was treated as rubbish! Angela didn't want her any more. She would have that silly Violet Hill who adored Angela from afar and would do anything to get a smile from her. Jane gave a sob and rushed out of the room. In a few minutes Violet Hill came in, thrilled to be sent for. Angela gave her orders in a lazy voice, amused to see how the little first former almost trembled with excitement as she tidied up the room and hung on Angela's lightest word."
 * Hide Your Lesbians: Bill and Clarissa. YMMV on this one because, though it's a widely accepted fan theory, it's not canon. They're both explicitly mentioned as being very tomboyish (Bill more so), and when they grow up instead of going to university and getting married like the rest of the girls they run a stables together.
 * Could apply to Alicia and Betty too - they're best friends who hang around an awful lot for people in completely different houses, and it's established in one of the books that they regularly sneak around at night together, but like most non-canon examples of this trope it's probably really just an imagined extension of a fifties-style Romantic Two-Girl Friendship.
 * Les Yay: Alison has this a lot, with Hot for Teacher antics and slavelike devotion to Sadie and Angela.
 * There's also a lot of subtext in the crushes younger girls who "admire" Angela have in the later books. Being a bit of an Alpha Bitch (although perhaps without so much alpha), she frequently takes advantage of their affections to make them do chores for her, sets them up in rivalries with each other or takes sadistic pleasure in hurting their feelings. Just look at this:


 * Too Dumb to Live: Amanda. She went swimming in the sea despite being warned that it was incredibly dangerous and that there was a fast current. End result: she nearly got killed and her career was effectively over. Moron.