Paulina being essentially a Latina version of Liz Allan when, in The Spectacular Spider-Man, Liz was given a Race Lift and is Latina in the show... and interestingly she looks very similar to Paulina, as well.
Kwan also seems to be based off Kenny McFarlane, and Kenny was made Asian in Spectacular.
The episode titled "Shades of Gray" can't get into some people's minds without thinking about Fifty Shades of Grey, which only gets better two seasons later in "D-Stabilized" when Valerie Gray has Danny tied up in her underground lair and tortures him with a cattle-prod-like weapon...
During a battle with Vlad in the first episode of Season 3, Danny is shocked at how "rusty" he's apparently gotten and how easy it is to beat him, remarking throughout the fight how "you've really lost your edge." In context, it turns out Vlad's so weak because he's currently split himself into hundreds of duplicates that he's using to possess everyone in town, but considering the Villain Decay he suffered from this point onward, it sounds like Danny's Leaning on the Fourth Wall.
So Danny's having trouble controlling his new ice powers due to lack of use and needs to learn to "let it out"... Just try to re-watch the Season 3 episode "Urban Jungle" without hearing "Let It Go" in your head.
Ember McClain is an evil musician from another dimension with a teal color scheme, has a pony tail, and uses her music to hypnotize people. Doesn't that remind you of another similar villainess? Even better, Ember is voiced by Tara Strong, who played a major character in that franchise.
In 2012, it took fangirls no time to notice that Danny looks just like a 2D-animated version of another ghost boy with ice powers, who has a very similar relationship with his story's Big Bad.
The episode, Teacher Of the Year, may have been made 7 years before Ready Player One (14 years before the movie), but the similarity of the in-universe game's goal to win the internet (OASIS in the case of Ready Player One) made it feel like one.
In "Infinite Realms", Tucker over-exaggerated how hungry he was and asks Sam to tell his PDA he loved her and the cell phone meant nothing to him. To show how this series became an Unintentional Period Piece, cell phones have become more advanced to the point where they are capable of everything a PDA had done, making them obsolete. If this were made in more recent times or continued further, Tucker would be saying the opposite instead.
"Reality Trip" showed the Reality Gauntlet, an object clearly based on the Infinity Gauntlet. At the time, few people outside of the diehard Marvel fans were aware of it and its significance. Years later came the start of the Marvel Cinematic Universe, which make the Infinity Gauntlet a more recognizable object. Perhaps, had the show continued or be revived, we would have seen a ThanosExpy.
On the subject of Thanos, "The Ultimate Enemy" has Dark Danny say, "I'm inevitable," years before Thanos himself would say the same thing in Avengers: Endgame. Fittingly, in his "10 Years Later" videos, Butch Hartman drew one of his interpretations of Dark Danny as looking like Thanos.
A blonde, blue-eyed caucasian girl named "Star" would be a more prominent character years later.
In "Pirate Radio", when Mr. Lancer reveals an "anonymous donor" sent Casper High a vinyl album causing Tucker to bemoan, "What is this, the stone age?" After the series ended, Vinyl would see a resurgence that lasted well over a decade. Meanwhile, PDA's which the technology-crazed Tucker obsessed over, would become obsolete.
The Guys in White, expies of The Men in Black, seen most in the series are called Agent O and Agent K. While the franchise that inspired them already had an Agent K, Men in Black 3 in 2012 would introduce its own Agent O, who had a romantic attachment to Agent K. And then there's this scene.
from Funko Pop! would ultimately come true