I tend to think of either American style names, nature names and nicknames when I think unisex.
So:
Aubrey, Ashley, Ashton, Brooklyn, Brogan, Brynn, Braelyn, Casey, Cassidy, Courtney, Cameron, Dylan, Dakota, Elliot, Eden, Emery, Emerson, Farrow, Fallon, Genesis, Harley, Hayden, Jaelyn, Jordan, Jayden, Kennedy, Marley, Morgan, Mason, Madison, Mackenzie, Presley, Quinn, Riley, Reese, Sutton, Spencer, Sydney, Sayler, Tyger
Blue, Beau, Journey, Jay, Meadow, Ocean, Phoenix, River, Red, Rain, Rowan, Robin, Raven, Storm
Andi/Andy, Charlie/Charley, Danni/Danny, Nikki/Nicky, Alex, Frankie, Harri, Stevie, Billie/Billy, Bobbie/Bobby, Mikki/Micky, Ally