Shout Out / qxlkbh

• The alt text of 9: title drop references the "roll credits" Running Gag from CinemaSins regarding title drops.
• 42: Regarding Tvtropes shouts out this very page, introducing both Mustache Twirler and the glider to the mainline comics for the first time so that they could be troped. The alt text, meanwhile, shouts out The Hitchhiker's Guide to the Galaxy by insisting that there will be no shout-out to Hitchhiker's Guide.
• In Q&A 4, Musi makes reference to a baseball player named "Who", a reference to Abbott and Costello's Who's on First? routine.
• 53: my hobby is a reference to xkcd's "My Hobby" strips. These are normally intended as soapboxes for the author, but the strip parodies this by having Baseball Cap refuse to cooperate with what's being said.
• 64: another milestone references xkcd's 1000th comic indirectly though the Alt Text "Only 36 to go until a... round... um, nevermind" which references the Cueball in xkcd 1000.
• proto-2 is just a Garfield strip with different dialogue.
• qxlkbh minus, uh qxlkbh? is 8: beat panels but with the cueball being the only character, as a reference to Garfield Minus Garfield.
• 65: Action Logic #1 and 66: Action Logic #2 are named in reference to the first two issues of Action Comics.
• The Alt Text of 66: Action Logic #2 references the Spider-Man quote "With great power comes great responsibility".
• The alt text of 67: Future ancient literature references the infamous "Loss" comic from Ctrl+Alt+Del and the resulting minimalist memes.
• The titles of 68, 69 and 70 all start with "the one", referencing the Idiosyncratic Episode Naming scheme from Friends.
• The archaeologist in 69: the one that continues the titling convention discusses a certain ancient hymn and speculates that it was used for curses. The song in question? Rick Astley's "Never Gonna Give You Up".
• The alt text of 78: descent is "jan Musija is leaving the building!"
• 92: filler references this Filler Strip from early on in xkcd's run.
• 104: changing up form a little, a chart cites The Divine Comedy as an example of a religious Self-Insert Fic.
• One secret page shouts out Olivier Messiaen.
• 107: the definitive guide to strip 107 mentions that zAlicerg is "extremely touchy about whether the drapes, carpet, and upholstery match", likely a reference to this comic from xkcd.
• 111: francium synthesis contains a reference to Conway's Game of Life's reverse caber tosser (which at the time of the comics creation required a total of 15 gliders to create) and features a pattern in which the Glider collides with a constellation made of blocks of francium.
• In 113: survivor bias:
  • An image on the TV screen in the second panel contains the text "Airplane? What is it?"
  • Person McPherson's unsuccessful attempt at adding an image to a social media post is a reference to this tweet by sports commentator Stephen A. Smith. Their account username contains the string "1745325", which is the numerical page ID for the English Wikipedia page Survivorship bias.
• 115: qxzlkbh once again references this page, in particular the fact that Finger-Tenting was commented out from the trope list due to it referring to a piece of official character art that was only available on Discord and thus did not count as "published".
• The alt text of 116: timeline mentions the character of Phil Connors, who exploits the time loop he's in to do whatever he wants with no consequences.
• 117: thinking with... handsaws? references the Tagline "now you're thinking with portals" from Portal.
• The alt text of 118: beard mentions the episode "Who Shaves the Barber?" of Fargo, which by meeting Wikipedia's notability standards further complicates the disambiguation hatnote for the article "barber paradox".
• The name of 120: seecret saturday update references Minecraft's "Seecret Updates" during its Infdev and Alpha stages. Most of these were released on Fridays and referred to as "Seecret Friday", but the last one was released on Saturday instead.
• The alt text of 122: technobabble references the "1.21 jigawatts" of power needed for the DeLorean in Back to the Future.
• According to Ian, 126: qxlkbh - The Lost Episode is filled with The Velvet Underground references. Besides the name-dropping of the albums Loaded and Squeeze in the description, there's also one involving Metal Machine Music, one in which Moe Tucker is depicted as a lumberjack, and, given Andrew's mentioning of a character saying "So... he's gone Bananas?", possibly also one referencing The Velvet Underground & Nico banana. In the next paragraph, Ian goes on to mention that he was inspired to make a joke about the programming language Lisp after hearing about it from xkcd.
• The description of 136: introducing byzantine football mentions that the rules specify when dogs are and are not allowed to play the sport, in a reference to Air Bud.
• Upon encountering some toasters on a table, La Croix remarks "You know what they say: [...] not all toasters toast toast" in an inversion of a line from Hotel Mario.
• The alt text of 141: celebration compares the zvillainsrg to "the guy with the jewelry", referring to The Lord of the Rings.
• The bottom of 148: nomic part 7 shows the Glider from Conway's Game of Life being bounced back and forth between two pentadecathlons.
• The secret comic "99+epsilon" features a walrus talking to a man named Mr. Carpenter, a reference to Lewis Carroll's poem "The Walrus and the Carpenter".