What kind of names do you like aside from [name_f]Lexi[/name_f]? That might help narrow the focus to names that are to your taste.
[name_f]Lexi[/name_f] [name_f]Grace[/name_f], [name_f]Lexi[/name_f] [name_f]Elizabeth[/name_f], [name_f]Lexi[/name_f] [name_f]Rose[/name_f], [name_f]Lexi[/name_f] [name_f]Marie[/name_f], and [name_f]Lexi[/name_f] [name_f]Mae[/name_f] are all very common middle names that all flow nicely with [name_f]Lexi[/name_f].
Some combos with names I personally like:
[name_f]Lexi[/name_f] [name_f]Genevieve[/name_f]
[name_f]Lexi[/name_f] [name_f]Adela[/name_f]
[name_f]Lexi[/name_f] [name_f]Eliza[/name_f]
[name_f]Lexi[/name_f] [name_f]Maeve[/name_f]
[name_f]Lexi[/name_f] [name_m]Rowan[/name_m]
[name_f]Lexi[/name_f] [name_f]June[/name_f]
[name_f]Lexi[/name_f] [name_f]Violet[/name_f]
[name_f]Lexi[/name_f] [name_f]Evangeline[/name_f]
[name_f]Lexi[/name_f] [name_f]Celeste[/name_f]
[name_f]Lexi[/name_f] [name_f]Juliette[/name_f]
[name_f]Lexi[/name_f] [name_f]Elowen[/name_f]
[name_f]Lexi[/name_f] [name_f]Elise[/name_f]
[name_f]Lexi[/name_f] [name_f]Noelle[/name_f]
[name_f]Lexi[/name_f] [name_f]Camilla[/name_f]
[name_f]Lexi[/name_f] [name_f]Isolde[/name_f]
[name_f]Lexi[/name_f] [name_f]Matilda[/name_f]
[name_f]Lexi[/name_f] [name_f]Solene[/name_f]
[name_f]Lexi[/name_f] [name_f]Elysia[/name_f]
[name_f]Lexi[/name_f] [name_f]Elara[/name_f]
[name_f]Lexi[/name_f] [name_f]Claire[/name_f]
[name_f]Lexi[/name_f] [name_f]Wren[/name_f]