The series itself makes a load of references to SiIvaGunner. In fact, a lot of his songs are in the videos themselves. Sometimes it results in weird stuff like the World of Light getting invaded by Love Live! spirits.
Individual Episodes
"Something about Monster Hunter World Part 3" has 2 notable references within the first minute: The first is Spongebob's pineapple amongst the growths on the top of the Rotten Vale's entrance, and the second is a corpse of Meat Boy amongst the numerous skeletons.
"Something About Star Fox 64" has a segment that's a whole homage to Vaporwave, gratuitous Japanese included.
In the same episode, on Corneria, one of the screens shows a stylized advertisement for Brawndo.
In "Something About Kirby's Adventure" Nightmare begging for his life uses the same "I'll give you one of my planets!" line that King Cold said to Trunks in Dragon Ball Z.
"Something About Kirby Super Star" has Mace Knight use the same text-to-speech voice as Moonbase Alpha, and references the "John Madden" and "aeiou" memes from motdef's videos. Yoshi also uses the Moonbase Alpha text-to-speech voice in "Something About Yoshi's Island" and "Something About Super Mario World", but references to any motdef memes are absent in those cases.
When the Green Kir Bro turns Dark Meta Knight into curry, the Monster Hunter "So Tasty!" clip plays. When they each slowly take a bite, it's done in the same way as curry in Pokémon Sword and Shield.
"Something About Super Mario World":
The start uses a clip of pannenkoek2012 saying "to answer that [question], we need to talk about parallel universes."
Also early on, Mario uses the Backwards Long Jump to rocket off the beach and into Dinosaur Land, slightly lampshading the insane speeds one can get with it by having a Twinkle in the Sky.
When Mario returns to Bowser's Castle, he speedruns through it accompanied by a sample of one of MetalKingBoo's "Mario Screaming" videos.
Something About Fortnite: Battle Royale references the "Thanos Gun" quote from Dunkey's time with the game.
In Legendary & Mythical Pokemon Battle Royale ANIMATED, the Simlish Entei speaks in when making volcanos erupt is the first set of lines spoken by The Dog in Ukinojoe's Dog of Wisdom.
"Something About Super Metroid":
When Samus finds out Ridley's attacked the space station and taken the Metroid Hatchling, Jean-Luc Picard's iconic Big "NO!" from Star Trek: First Contact is used.
Samus approaches Ridley in a way that mirrors the memetic scene from Jojos Bizarre Adventure where Jotaro approaches Dio. Interestingly, Samus is in the villain's position.
Zebes is labeled "PLANET ZEBEBEBEBEBEBEBEBEBE", referencing Deepercutt's Static ShockYouTube Poop "$tatic 5hock the rip-off of electro", specifically the pieces where Mr. Hawkins repeats "BEBEBEBEBE" over and over.
In the SAVE ending, the Etecoons and Dachora are revealed to be X Parasites in disguise. Since this doesn't have any basis in the games' canonnote X Parasites are never found on Zebes, and Adam specifically states that he scanned them and verified that they were not infected in Metroid Fusion, this appears to be a reference to the Game Theory video on the same topic.
In "Something About Sonic the Hedgehog":
One of the Ball Hog Badniks is designed similarly to Peppa Pig.
When Dr. Eggman's glasses fall off, he's revealed to have the same black and red eyes as the Dr. Robotnik from Adventures of Sonic the Hedgehog
The animals inside the Badniks in Scrap Brain Zone in "Something about Sonic the Hedgehog" partially include Yoshi,Daroach, and a Rabbid.
When Link enters the Temple of Time, it still has a dramatic chanting music theme... to the tune of the The Flintstones.
The top triangle of the summoned Triforce shifts at the last second so that it's parallel to the bottom-left one. This nods back to a shibboleth on 4chan that attempts to out newbies by seeing if they can successfully create a Triforce with ▲ characters; most failures to do so result in the same configuration seen in the video.
Ganondorf reacts to the Triforce with audio from the intro to Mundial Ronaldinho Soccer 64, a bootleg version of International Superstar Soccer 64 themed around real-life Brazilian soccer players.
Ganondorf's dancing upon reaching the Triforce is rotoscoped from a viral gif◊ of a skeleton puppet.
In a blink-and-you-miss-it background moment, Crono, Lucca and Marle can be seen entering a house in Kokiri Forest.
In "Something About Mega Man X", X checks the weapons he's acquired and his default energy pellets are labelled as "lemons" in reference to Egoraptor's Sequelitis video on the game.
"Something About the Photon Aerospace Control Engineer" contains numerous references to Dead Space, such as the design of the engineer's suit and weapon, the ghosts resembling a mish-mash of corpses like the necromorphs, and the bloody writing saying to cut off their limbs, which is the primary way the necromorphs are killed.
"Something About The Subspace Emissary":
In its Closed Captions, "Million Dollar Baby'd" appears on screen when Tabuu falls sideways and breaks his neck.
When Speedrunner Mario accepts Super Chili Dogs (Sonic)'s duel, he quotes Tai Long in Japanese.
The narrator for the Versus Character Splash between Speedrunner Mario and Super Chili Dogs is reminiscent to the Skullgirls narrator.
"Something About Mega Man X: Storm Eagle's Revenge" features Daft Punk among the citizens.
"Something About Kirby and the Amazing Mirror": The 3rd thing Wiz pulls from his hat is Space Shuttle Atlantis, a nod to NASA's Space Shuttle Program.
"Something About Zelda Ocarina of Time PART 2: The FOREST TEMPLE" features Phantom Ganon performing a Cover Version of "Suavemente" by Puerto Rican singer Elvis Crespo, rendered with text-to-speech vocals and MIDI backing.
"Something About Undertale - Alternate Pacifist Route":
Toriel has a framed photo of Quote from Cave Story hanging on her wall.
Kirbo's flashback to the Egyptian enslavement of the Hebrews is represented with footage from The Prince of Egypt.
Kirbo using Spark Cutter to defeat HR-H is practically a Shot-for-Shot Remake of Raiden cutting off Metal Gear RAY's right arm in Metal Gear Rising: Revengeance. The background music even plays Rules of Nature!
Endogeny's battle theme from Undertale plays when Adeleine is menaced by a Glom in Shiver Star's mall.
When Adeleine encounters the aforementioned Glom, her hair briefly spikes out in a similar fashion to Chihiro's hair when she first encounters the Stink Spirit in Spirited Away.
"Something About Kirby's Dream Buffet":
As Meta Knight's gluttony gets the better of him, his body resembles No-Face's gluttonous form, especially as his mask becomes too small for it to cover his grotesque mouth. In addition, Meta Knight's obsession for chocolate culminates in him shouting "CHOCOLATE!"
"Something About Pokemon Legends Arceus":
The scene where Dawn's Wyrdeer sinks into the mud uses audio from the infamously tragic scene from The Neverending Story. ARTAAAAAX!
"Something About Buck Bumble":
The can of pesticide that Lardna Minch tries to use against Buck goes by the name "Shadow Legends".
"Something About Helldivers II"
When the team are selecting their loadout while heading to Malevelon Creek, J1, K3 and M2 recite the exchange about the the Series 4 De-Atomizer and the Noisy Cricket from Men in Black.
In The Stinger, one of the Helldivers happens upon the control room from which Joel, a dog, is controlling the rate of the Automation's Bot Drops. Cue the "Dog Ending" exchange from Silent Hill 2... until Joel calls down a Bot Drop.