Realistically: In my country some names that are considered modern are Gioia (“joy”), Mia, Luna, Nina, Stella (“star”), Sole (“sun”), Neve (“snow”), Andrea (g), Asia, Futura (“the future one”) Gala, Olivia, and Ariel. I would use Gala, Stella, Neve, Sole, Andrea, Mia or Ariel. Maybe Olivia and Nina.
If I lived in an English speaking country… Poet, Lavender, Rowan, and so many!
[name_u]Ocean[/name_u] is the only one that comes to my mind 
[name_f]Persephone[/name_f] should be considered as modern, so I’ll go with that. If not, I suppose [name_f]Cleopatra[/name_f] or [name_f]Clover[/name_f]?
[name_u]Wren[/name_u].
I would switch gears and go for something short / shorter than their first names.
[name_f]Nola[/name_f]
[name_u]Vida[/name_u]
[name_u]Briar[/name_u]
[name_f]Odessa[/name_f]
[name_f]Maris[/name_f]
[name_u]Blue[/name_u]
Some ‘modern’ ones on my faves list include:
[name_u]Glow[/name_u], Indie/Indigo, [name_u]Romilly[/name_u], [name_u]Kestrel[/name_u], [name_u]Camber[/name_u], [name_u]Kerrigan[/name_u], Mabli*, [name_u]Hero[/name_u], [name_u]Everett[/name_u], [name_u]Lark[/name_u], [name_f]Bronte[/name_f], [name_u]Winter[/name_u], [name_f]Jovie[/name_f], [name_u]Sailor[/name_u], Carys*
Realistically, [name_f]Mabli[/name_f] or [name_f]Bronte[/name_f] would be the ones I’d pick. [name_f]Bronte[/name_f] for it’s literary ties, its thundery meaning and surname-y vibe. [name_f]Mabli[/name_f] for its sparky, distinctive sound and beautiful meaning - it is a Welsh name from the 1900s but its only recently had a resurgence of interest!
Surprisingly there is actually a lot of ‘modern’ names that I would consider!
I love day names like [name_f]Sunday[/name_f], [name_f]Tuesday[/name_f] & [name_f]Wednesday[/name_f] I think they are lovely however my favourite is definitely [name_f]Sunday[/name_f] ‘Sunny’ she’s so sweet!
I have these surname choices [name_u]Marlowe[/name_u], [name_u]Rooney[/name_u] & Lockhart on my list as middle names. I also love [name_f]Winslet[/name_f], [name_u]Winslow[/name_u], [name_u]Piper[/name_u] and [name_u]Oakley[/name_u].
[name_u]Shiloh[/name_u] & [name_u]Eden[/name_u] are such cool biblical place names.
I also love [name_u]Rowan[/name_u], [name_u]Juniper[/name_u], [name_f]Lavender[/name_f], [name_u]Indigo[/name_u], [name_f]Lilac[/name_f], [name_f]Lyra[/name_f], [name_f]Bloom[/name_f], [name_f]Elowen[/name_f], [name_u]Coast[/name_u], [name_u]Ocean[/name_u], [name_f]Autumn[/name_f], [name_u]Lark[/name_u], [name_u]Winter[/name_u], [name_u]Wren[/name_u], [name_u]Sparrow[/name_u], [name_f]Meadow[/name_f], Clove/Clover and [name_u]Bay[/name_u]. Along with non nature word names like [name_u]Fable[/name_u], [name_u]Poet[/name_u], [name_u]Hero[/name_u], [name_u]Story[/name_u] and [name_f]Sonnet[/name_f].
I also love [name_f]Delphi[/name_f] this feels modern but technically isn’t.
So I think if I had to give my daughter a modern name and she was born today I would go with [name_f]Sunday[/name_f] [name_f]Lavender[/name_f] [name_u]Marlowe[/name_u] 
[name_f]My[/name_f] favourites are [name_f]Autumn[/name_f], [name_u]Briar[/name_u], [name_f]Faye[/name_f], [name_u]Haven[/name_u], [name_u]James[/name_u], [name_u]London[/name_u], [name_u]Monroe[/name_u], [name_u]Ozzy[/name_u], [name_u]Parker[/name_u], [name_u]Rhodes[/name_u], [name_u]Sage[/name_u], [name_f]Sunday[/name_f], [name_u]Tatum[/name_u], [name_u]Willow[/name_u].
[name_f]Amaranth[/name_f]
Falun
[name_u]Soma[/name_u]
Mauren
Flavienne
It’s 3 AM, so I’m either a genius, or insane.
[name_u]Juniper[/name_u]! [name_u]Or[/name_u] [name_f]Harlowe[/name_f], maybe. [name_u]Juniper[/name_u] [name_f]Harlowe[/name_f]?
[name_f]Birdie[/name_f]
[name_f]Danica[/name_f]
[name_u]Esme[/name_u]
[name_u]Greer[/name_u]
[name_u]Indie[/name_u]
[name_f]Lola[/name_f]
[name_f]Lottie[/name_f]
[name_f]Poppy[/name_f]
[name_u]Scout[/name_u]
[name_f]Vallie[/name_f]
I would choose something like:
[name_f]Topanga[/name_f]
[name_u]Rivers[/name_u]
[name_u]Carden[/name_u]
[name_f]Ayla[/name_f]
[name_f]Marga[/name_f]
[name_u]Frankie[/name_u]
[name_f]Bren[/name_f]
[name_f]Olive[/name_f]
[name_u]Dell[/name_u]
[name_u]Bellamy[/name_u]
[name_u]Seren[/name_u]
[name_f]Trina[/name_f]
[name_u]Haze[/name_u]
[name_f]Nonie[/name_f]
[name_u]Ollie[/name_u]
[name_m]Len[/name_m]
[name_f]Leni[/name_f]
[name_u]Lennox[/name_u]
[name_u]Lennon[/name_u]
[name_u]Lisha[/name_u]
[name_f]Liel[/name_f] or [name_f]Lielle[/name_f]
[name_u]Tilden[/name_u]
[name_f]Cosma[/name_f] or Cozma
[name_u]Ira[/name_u]
[name_f]Terra[/name_f]
[name_f]Nica[/name_f]
[name_f]Vica[/name_f]
[name_u]Mirren[/name_u]
[name_f]Yeva[/name_f]
[name_f]Opal[/name_f]
[name_f]Aura[/name_f]
[name_u]Isa[/name_u] or [name_f]Iza[/name_f]
[name_f]Raia[/name_f]
[name_f]Lula[/name_f]
[name_f]Lulu[/name_f]
[name_f]Celie[/name_f]
[name_f]Zara[/name_f]
[name_u]Zephyr[/name_u]
[name_f]Myka[/name_f]
[name_u]Alva[/name_u]
[name_u]Albie[/name_u]
[name_u]Gentry[/name_u] or [name_f]Jentry[/name_f]
[name_u]Kendall[/name_u]
[name_u]Maven[/name_u]
[name_u]Seeley[/name_u]
[name_u]Tallie[/name_u]
[name_f]Lune[/name_f]
[name_f]Line[/name_f] (pronounced leen)
[name_u]Eden[/name_u]
[name_f]Effie[/name_f]
[name_f]Ginny[/name_f]
[name_f]Lani[/name_f]
[name_u]Hollis[/name_u]
[name_u]Collins[/name_u]
[name_m]Seldon[/name_m]
[name_u]Galen[/name_u]
[name_u]Fallon[/name_u]
[name_m]Calvin[/name_m]
[name_u]Jo[/name_u]
[name_f]Holiday[/name_f]! I used to have [name_f]Holiday[/name_f] [name_f]Jane[/name_f] on my list, I would totally go for that!
ones i like: darcie, charlee, marlee, georgie, skye, stella
i would choose darcie stella
I love [name_u]Ever[/name_u] right now. Probably my top name for a girl. I have a quiet affinity for “kardashian kid names”. I love their [name_u]True[/name_u], [name_u]Dream[/name_u], [name_u]North[/name_u]. I’ve never been crazy for modern names, but this style just works. It’s unique without being flashy and way better than the -lyn / -ton modern name trend.
I also love classic boy names on girls.
Some favorite modern girl names:
[name_u]August[/name_u]
[name_u]Auden[/name_u] / [name_u]Arden[/name_u]
[name_u]Asa[/name_u]
[name_u]Dove[/name_u]
[name_u]Forest[/name_u]
[name_m]Hart[/name_m]
[name_u]River[/name_u]
[name_u]Arrow[/name_u]
[name_u]Willow[/name_u]
love the sounds of larkin & romilly!
Today I would go with [name_f]Wednesday[/name_f]
[name_u]Hadley[/name_u], [name_u]Willow[/name_u], [name_f]Sunday[/name_f], [name_u]Prairie[/name_u]
[name_u]Lennon[/name_u]! I love [name_u]Lennon[/name_u] for a girl.
[name_u]Blake[/name_u], [name_u]Hadley[/name_u] or [name_u]Harper[/name_u]! I was a little stuck on whether a name is modern or not lol. So some others that might fit the bill: [name_f]Savannah[/name_f], [name_f]Verity[/name_f], [name_f]Vada[/name_f], [name_u]Frankie[/name_u], [name_f]Liv[/name_f], [name_f]Nola[/name_f], [name_u]Blythe[/name_u].