Boys:
[name_m]Fraser[/name_m] - Fray/[name_m]Frey[/name_m]
[name_m]Frederick[/name_m] - [name_m]Fritz[/name_m] is my favorite for this name
[name_m]Rafferty[/name_m] - [name_m]Raff[/name_m] is all I can think of for this
[name_m]Rupert[/name_m] - [name_u]Rue[/name_u]
If there’s an F-nickname you like, such as ‘[name_u]Finn[/name_u]’, for example, I’d say feel free to use it for either [name_m]Fraser[/name_m] or [name_m]Frederick[/name_m] too.
Girls:
[name_f]Faye[/name_f] - you could extend the name out?? Maybe something like [name_f]Faye[/name_f]-a [name_f]Faye[/name_f]-lee [name_f]Faye[/name_f]-linn… those are what would develop naturally I think, because people like to add -ella,-lee,-lyn to the end of girls names.
[name_f]Florence[/name_f] - [name_f]Flora[/name_f], [name_u]Ren[/name_u], [name_f]Rena[/name_f], Floren
[name_f]Sybil[/name_f] - Sybi
[name_f]Sylvie[/name_f] - [name_m]Sil[/name_m], Sylv, Vee
I always think [name_u]Red[/name_u] would be a cool nn for [name_m]Frederick[/name_m]. Maaaybe [name_m]Fox[/name_m] / Fix? [name_m]Eddie[/name_m] / [name_m]Eddy[/name_m] would work too.
[name_u]Asa[/name_u] or [name_m]Ace[/name_m] could be options for [name_m]Fraser[/name_m].