I first thought of [name_f]Coco[/name_f], [name_f]Bella[/name_f], [name_f]Thea[/name_f], [name_f]Etta[/name_f], [name_f]Dora[/name_f], [name_f]Della[/name_f] and [name_f]Bea[/name_f], as others have said!
Some that I haven’t seen mentioned yet - although note that lots of these are names on their own as well:
[name_f]Margo[/name_f] (Margaret?)
[name_m]Jojo[/name_m] (Josephine, Joanna,)
[name_f]Juno[/name_f] (June, [name_f]Juniper[/name_f])
[name_f]Lola[/name_f] (Dolores, Charlotte?)
[name_f]Sasha[/name_f] (Alexandra, Alexandria?)
[name_f]Sanna[/name_f] (Susanna? - I knew a girl named [name_f]Sienna[/name_f] who her close friends called her [name_f]Sanna[/name_f])
[name_f]Lila[/name_f] (Delilah)
Laylay / Leilei (Layla, [name_f]Leila[/name_f])
[name_f]Lana[/name_f] (Alana)
[name_f]Mila[/name_f] (Camila, Milena?)
[name_f]Trina[/name_f] (Katrina, Trinity?)
[name_f]Rina[/name_f] (Caterina, [name_f]Irina[/name_f], [name_f]Marina[/name_f])
[name_f]Tina[/name_f] (Christina, [name_f]Valentina[/name_f], [name_f]Martina[/name_f])
[name_f]Mara[/name_f] (Tamara, [name_f]Amara[/name_f])
[name_f]Mona[/name_f] (Ramona, Simona?)
[name_f]Donna[/name_f] (Madonna, Donatella?)
[name_f]Nora[/name_f] (Eleanor, [name_f]Leonora[/name_f], etc)
[name_f]Darla[/name_f] (Darlene)
[name_f]Rosa[/name_f] (Rosalie, [name_f]Rosalyn[/name_f], etc)
[name_f]Cora[/name_f] (Coraline, [name_f]Coralie[/name_f], [name_f]Corinne[/name_f], etc)
[name_f]Hope[/name_f] this helps!