A theory I showed off at a discord server now turned into a full on connection theory.
Evidence[]
PART 1: Live Action[]
The connections start with the Big Time Rush episode, "Big Time Beach Party" in which Patchy the Pirate guest stars, This is the only time we would get a SpongeBob crossover.
PART 1.5: Yo Gabba Gabba[]
Yo Gabba Gabba's popularity lead into the middle core with crossover episodes, and Big Time Rush is one of them, As they appear in 2 episodes of the series. They have also appeared in Raising Hope (connects to My Name is Earl), The Fresh Beat Band (which connects to Fresh Beat Band of Spies), and True Jackson VP
PART 1 cont'd: Live Action[]
Steve from Blue's Clues appears in Yes Dear and also appears in Jack's Big Music Show (which connects to Laurie Beckner and South Park), and Yo Gabba Gabba.
Fred's father is potrayed by John Cena (which connects to WWE).
Supernatural connects to Scooby Doo and G.I. Joe because they have made crossover episodes
Big Time Rush appears in How to Rock and Marvin Marvin (which connects to Fred: the Show, Annoying Orange, and Weird Al).
Fred appeared in iCarly, which connects it to All That, The Amanda Show, Drake and Josh, Victorious, Sam and Cat, Henry Danger, Game Shakers and Danger Force
Fred's father is potrayed by John Cena (which connects to WWE).
The Aquabats connects to Yo Gabba Gabba because a prototype Muno and Homestar Runner because the character of the same name and Strong Bad appeared in the kickstarter.
Weird Al has appeared as himself in a bunch of Live Action shows so they all connect.
PART 2: Animation[]
Weird Al has appeared in the Simpsons, (connects to Futurama, Robot Chicken, Family Guy and its spinoffs, Bob's Burgers and an Disney universe theory), Johnny Bravo (connects to Scooby Doo), Batman (which connects to Power Rangers, TMNT and the MCU), Rocky and Bullwinkle, Close Enough (connects to Regular Show, Adventure Time, O.K. KO!, Captain Planet, Sonic and the Cartoon Network universe), American Dad and Game Grumps (which connects to OneyPlays)
WWE has made specials with Scooby Doo, The Flintstones (which connects to The Jetsons) and The Jetsons.
PART 3: The connection completion[]
The MCU, John Cena, G.I. Joe, Star Wars, Batman all collaborated with Fortnite, So it connects with all of them.