Ones with love-hate relationships, say

• People in a love/hate relationship?
• Portmanteau for partners who are also competitors
• Besties who also literally hate each other's guts but we're besties but we hate each other so much it hurts sometimes
• Allies who are also rivals

Wikipedia Word definitions in Wikipedia
" Frenemies " is the ninth episode and spring premiere of the fifth season of the American musical television series Glee , and the ninety-seventh episode overall. Written by Ned Martel and directed by Bradley Buecker, it aired on Fox in the United States ...

Wiktionary Word definitions in Wiktionary
alt. (plural of frenemy English) n. (plural of frenemy English)