In "Wildfire," when they group is driving away after leaving Jim to die, as per his request, the wonderful "Sunshine (Adagio in D Minor)" from Sunshine plays, presumably as a Shout-Out to director Danny Boyle, who also directed 28 Days Later.
The preview for "Bloodletting" uses Johnny Cash's "I See A Darkness" to a truly haunting effect.
In "Nebraska", Clutch's "The Regulator" is used for a particularly haunting effect over the final scene of burning the barn Walker bodies.
Wye Oak's "Civilian" is used in the main trailer for Season 2, as well as the episode "18 Miles Out" when Rick is driving back to the farm at the end of episode.
Kari Kimmel's "Black", for the Season 3 debut trailer. Fight the Dead. Fear the Living.
Tom Waits' Hold On is used, and sung by Beth Greene, at the end of "I Ain't No Judas".
In "Alone", Beth performs Waxahatchee's "Be Good" on a piano. Much like the Hyundais featured in the show, the song can't logically exist in the show's universe, as it was written in 2012.
In "Consumed", "Bad Blood" by Alison Mosshart and Eric Arjes plays over the prologue showing Carol's perspective between the episodes "Indifference" and "Too Far Gone". It's a slow, heart-wrenching song that perfectly accommodates Carol's grief over being exiled from the prison by Rick.
The quiet, ethereal piece during Tyreese's death is soothing and gentle, as Tyreese accepts his fate and passes on to the afterlife, and the group dejectedly buries him, and is forced to move on.
"We Carry On" by The Phantoms is used in a trailer for Season Six. It really sells one of the main themes of the series - "we will stand stranger to brother, we are one, we carry on." It plays over some cool visuals of the main cast of the season, the cast member in focus transitioning under a revolving light from above. Especially cool is Morgan's presence towards the end, confirming his return to the ensemble and as a major character to boot.
The epic track during the walker mission in "First Time Again" is haunting and epic as we see the group take on their biggest mission yet. There are sounds during the piece that sound like a cross between an automated car assembly line and a vocalist that help portray the unthinking machinery of the herd.
The piece at the end of "Start to Finish" has great piano as Deanna makes her Last Stand and the others exit the Anderson home Covered in Gunge. It really picks up as Rick's group stands on the porch, bracing themselves to step off into the danger of the open herd, and considering The Stinger, also brace themselves for the unknown and the darkness on the horizon whose name is Negan.
The Battle of Alexandria in "No Way Out" is accompanied by a great soundtrack, first a down and dirty section as Rick's group and the Alexandrians unite on the battlefield. Then once Daryl arrives with the RPG, the music turns hopeful with a bunch of strings, as Rick leads the final charge to take back their home.
Hozier's "Arsonist's Lullaby" at the end of "Not Tomorrow Yet" nicely underscores the group's emotions after their attack on the Savior compound.
"It's All Over" by Johnny Cash near the beginning of "East."
The piece during Eugene volunteering to make his Last Stand in "Last Day on Earth" is heart-wrenching and beautiful, as it perfectly captures the group's gratitude for Eugene's actions, Abraham and Eugene bidding each other farewell for the last time as the Season 7 premiere reveals, and Eugene trying to muster up the courage to stay the course, even in this Darkest Hour.
It's just barely there, but during the big Negan scene in "Last Day on Earth", there are these scratchy strings playing throughout (notable in one shot of Glenn after Negan introduces Lucille) that really sell the writhing frustration and anxiety of watching Negan play with his prisoners.
The track that plays during the actual victim picking with Lucille really helps regain all the terror and anxiety that the audience lost when the cliffhanger abruptly ended the Season 6 finale.
The tune that plays during "The Day Will Come When You Won't Be" as Rick collapses atop the RV is absolutely heartbreaking.
"The Well" gives us a haunting, but gorgeous choral cover of Bob Dylan's "Don't Think Twice, It's All Right". It's a great comedown from the horrors of the Season 6 finale, Season 7 premiere, and all the speculation and frustration during the seven month long cliffhanger.
"The Cell" features Roy Orbison's "Crying", and opens up with The Jam's "Town Called Malice".
"Alive Inside", first played in the pharmacy office in Macon, plays during scenes with Clementine. A moving, crushingly sad version is played during the final scene when Lee tells Clem his final words.
"It's Over", which has played in major sad moments since Episode 2, particularly when leaving the St. John Dairy, when Kenny and Katjaa are deciding what to do with a bitten Duck, and when the player drops Ben to his death.
"Armed With Death", played only during Lee's potentially one-armed rampage through the streets of Savanna, which are infested with a horde of walkers.
"Take Us Back", by Alela Diane in the credits for the last episode of season one. It certainly punctuates the emotional roller coaster of Episode Five.
"Hope", which plays during some of the more uplifting scenes, such as when Carley flirts with Lee in Episode 3, where it is first heard, or when Lee's group discovers a functioning boat in Episode 4.