So, like the last playlist journal I did:
[link] this entry is the song list excluding the anime intros for the D.Gray-Man anime.
The theme of this playlist is Celtic Teen Pop. I chose this theme because Tock and Kanda are, to date, the youngest character's I've worked with and I wanted to reflect that in the music. Tock is Irish so I also wanted to throw in some Celtic music.
Can't Help Falling in Love-A*Teens: Yes, I'm a 90's kid born and raised. This song by the Swedish pop group reflects the kind of love teenagers like Kanda and Tock share, even if they are far from normal teenagers. It also sets the stage for the type of songs you'll be hearing.
C'est La Vie-B*Witched: This song by the Irish pop group (also from the 90's) reflects the Celtic theme of the playlist as well as how Tock courted Kanda when she was still Eva (i.e., in her human body)
Summer Sunshine-The Corrs: Another Irish pop group, this song is good for images of Tock flying with Kanda on her back. The line: "From sweet beginnings, to bitter endings" is more appropriately set to visions of her hitting him over the head at various moments. Those of you who are up on the manga should have a good idea as to which moments I'm referring to.
I'll be at your Side-The Corrs: This one reflects Tock and Kanda's partnership.
I'm Gonna Fly-The English version from Kiki's Delivery Service: This song is in here because Tock has the power of flight.
To the Sky-Owl City: The only song I like by this kid, this song is on here because flying.
I'm only me when I'm with you-Taylor Swift: This song greatly fits how, when Tock and Kanda are alone, they can actually let loose and be goofy kids like they should, instead of warriors.
Life with You-Celtic Thunder & George Donaldson: This song is like an Irish version of Just haven't met you Yet by Michael Buble. You can put that song on the list too actually. They both fit.
Carolina Rua-Celtic Woman: Actually my personal playlist has a sh!t ton of Celtic Woman songs on there. This song, however, more reflects Kanda's feelings about Tock.
King of Anything-Sarah Bareilles: This song is one of my personal favorites. It reflects how Tock, when she and Kanda were first paired, clashed completely. Tock refused to follow Kanda's commands. 'Who put you in charge? Eh boyo?'
Send me on my Way-Rusted Root: This song represents how globe trotting being an exorcist can be. In my mind, this is the song Tock gets Kanda to dance with her to.

Other Celtic bands you should check out:
Celtic Thunder
Celtic Woman
The Tossers
Tempest
Gaelic Storm
Flogging Molly
Dropkick Murphys
Celtic