Besides variations of [name_f]Elizabeth[/name_f], what other names can [name_f]Buffy[/name_f] be a nickname for?
A few ideas:
[name_f][/name_f][name_f]Bettina[/name_f]
[name_f][/name_f]Bartholomea / Bartholomina
[name_f][/name_f][name_f]Bernadette[/name_f]
[name_f][/name_f][name_f]Bathsheba[/name_f]
[name_f][/name_f]Basemath
[name_f][/name_f][name_f]Blanchefleur[/name_f]
[name_f][/name_f][name_f]Annabeth[/name_f]
[name_f][/name_f][name_f]Elsabeth[/name_f]
[name_f][/name_f][name_f]Bethia[/name_f]
[name_f][/name_f][name_f]Bethania[/name_f]
[name_f][/name_f][name_f]Lilybeth[/name_f] / Lillibeth
[name_f][/name_f][name_f]Marybeth[/name_f]
[name_f][/name_f][name_f]Bethesda[/name_f]
[name_f][/name_f]Florabeth
[name_f][/name_f][name_f]Hephzibah[/name_f]
[name_f][/name_f][name_f]Tabitha[/name_f] / [name_f]Tabatha[/name_f]
[name_f][/name_f][name_f]Bertha[/name_f] / Abertha
[name_f][/name_f][name_f]Alberta[/name_f] / [name_f]Elberta[/name_f]
Some of these might be a bit much but 
[name_f]Buffy[/name_f] as a nickname for…
[name_f][/name_f][name_f]Tabitha[/name_f]
[name_f][/name_f][name_f]Bethany[/name_f]
[name_f][/name_f][name_f]Blythe[/name_f]?
[name_f][/name_f][name_f]Bethel[/name_f]
[name_f][/name_f][name_f]Bethan[/name_f]
[name_f][/name_f][name_f]Fabia[/name_f]
[name_f][/name_f][name_f]Fioralba[/name_f]
[name_f][/name_f]Aberfa
[name_f][/name_f][name_f]Bathsheba[/name_f]
[name_f][/name_f]Bellaflore
[name_f][/name_f]Febronia
[name_f][/name_f]Floribel
[name_f][/name_f][name_f]Alberta[/name_f]
[name_f][/name_f][name_f]Albertine[/name_f]
[name_f][/name_f][name_f]Bethsabee[/name_f]
[name_f][/name_f][name_f]Thisbe[/name_f]