Keelan sounds very modern to my ears but, having looked online, it seems to be loosely related to the Gaelic name, Caolán.
Perhaps she might like another Celtic name?
Hard to know what to suggest on so little information but perhaps:
Keelan &
Blaise, Blake, Brendan, Bryn, Caleb, Damian, Dexter, Dorian, Duncan, Elliot, Everett, Ewan, Fabian, Finnian, Flynn, Gareth, Gavin, Gethin, Gregor, Ivo, Jude, Logan, Micah, Macsen, Magnus, Owen, Orion, Otis, Patrick, Roman, Riley, Rory, Sean, Sol, Soren, Stefan
Adelaide, Adele, Ailsa, Alessa, Allegra, Astrid, Aurora, Beatrix, Briella, Callista, Carla, Carys, Ceri, Clio, Dana, Eden, Eleni, Eleri, Eliana, Ella, Elodie, Felicity, Fiona, Harper, Hope, Isadora, Jada, Kara, Luna, Maisie, Megan, Nova, Pia, Pippa, Romola, Sasha, Scarlett, Sienna, Tessa, Zoe