Ones I think "work":
Hazel and
HugoAva and
AlexanderSophia and
SamuelPenelope and
PaxChloe and
CalebLily and
LukeGrace and
GavinImogen and
IsaacJuliette and
James (
Julia and
James would work better)
Taylor/Tyler, Christian/Christina and Madison/Mason are probably the worst in terms of matchiness. I'm also particularly annoyed by ones that aren't similar in style at all -
Savannah and
Sebastian,
Claire and
Clive.
Noah and
Naomi I like together on paper, but I feel like they'd be pretty tongue-twisty irl.
Sophia/Samuel, Ava/Alexander and Imogen/Isaac are the most complimentary imo. I like Penelope/Pax a lot too.
I'm actually kind of fond of twin names starting with the same letter. I wouldn't go out of my way to avoid in, in any case.
http://www.behindthename.com/pnl/87410