Reaper's voice line, "I'm back in black," references the song and album of the same name by the rock band AC/DC.
The voice line for Reaper, "This is my curse..." is a possible reference to the song by the metalcore band Killswitch Engage.
The line "Dead man walking" references a longstanding phrase used to announce United States prison inmates being escorted to their execution. In the Warcraft Universe, the Lich Unit also uses the same line when executing an attack on an enemy Unit.
The line "I'm not a psychopath, I'm a high-functioning psychopath" parodies a similar line from the BBC television program Sherlock, where the title character insists he is a "high-functioning sociopath," rather than a psychopath.
The line "If it lives, I can kill it" references a similar line from the film Predator, where a character named Dutch surmises of the titular alien, "If it bleeds, we can kill it."
The line "Angel of Death" references Blizzard's Diablo 3, as in one of the characters named "Malthael" is also mentioned as "Angel of Death". "Angel of death" could also refer to Archangel Gabriel and his given name known as "Angel of Death" for bringing the messages of God to the unfaithful.
Reaper's datamined voice line "Come at the king, best not miss" is shared by Doomfist as a final blow voice line however Reaper's was discovered months prior.
Both of Reaper's Summer Games voice lines are shortened versions of the original voice lines that have been datamined prior to the event.
Reaper's voice line "It's in the refrigerator" is a reference to NBA announcer Chick Hearn's famous quote "This game's in the refrigerator: the door is closed, the lights are out, the eggs are cooling, the butter's getting hard, and the Jell-O's jigglin'!"
The voice line "Just win" is another sports reference. It's based on the motto of the American Football team, the Oakland Raiders. The motto was coined by the team's owner, Al Davis
The line "It's just not the same since they cleaned up all the smog." is possibly in reference to Los Angeles, where Reaper had likely lived before Overwatch.
The line "What kind of name is Doomfist anyway?" is likely a reference to Call of Duty 4: Modern Warfare, specifically the quote from Captain Price stating "What kind of name is Soap anyway?"
The line "The man in black followed" is likely a bastardisation of the quote "The man in black fled across the desert, and the gunslinger followed" from the Stephen King's 'The Gunslinger' ('The Dark Tower', #1).
Despite being an unused quote, the line "Killing is as easy as breathing" is a reference to the 2008 film Rambo.