1.When Abed from Community showed up in the background of Cougar Town.
2.When Parks and Recs star Li'l Sebastian wound up The Good Place.
3.The fact that Ursula from Mad About You is the twin sister of Phoebe from Friends.
4.And when Kramer from Seinfeld had a little cameo in Mad About You.
5.When the guys from Sarah Jane Adventures and Torchwood showed up to help save the day in Doctor Who.
6.Pretty much every Arrowverse crossover, but especially Crisis On Infinite Earths.
7.And of course the Supergirl and Flash crossover, where everyone was stuck in musical.
8.When Olivia Pope from Scandal showed up to give Annaliese Keating her support in How to Get Away with Murder.
9.When Raven, Miley, Zack, and Cody joined forces for That's So Suite Life of Hannah Montana.
10.And of course, Wizards on Deck with Hannah Montana.
11.When The Jetsons traveled back from the future and ran into The Flintstones.
12.The Jimmy Timmy Power Hour – a crossover ~trilogy~ where Jimmy Neutron and Timmy Turner's worlds collided.
13.When Jess from New Girl went to New York and ran into Jake from Brooklyn Nine-Nine.
14.When Carly and Tori dated the same guy and iParty with Victorious was born.
15.When Booth from Bones had a vision of Stewie from Family Guy.
16.When Michael from Arrested Development went on a TV studio tour and interrupted the filming of Malcolm in the Middle.
17.The episode of How I Met Your Mother where Hurly from Lost showed up
18.When Steve from Family Matters visited Stephanie from Full House to make her feel better about wearing glasses.
19.When Archer from went undercover and worked at the restaurant in Bob's Burgers.
20.When Salem from Sabrina the Teenage Witch sent the kids from Boy Meets World back in time.
21.The episode of Boy Meets World where Salem from Sabrina the Teenage Witch showed up and wreaked havoc
22.When the kids from Phineas and Ferb had to worked with The Avengers to save Danville from a bunch of villains.
23.When Mulder and Scully from X-Files showed up on The Simpsons .
24.When Gretchen from Unbreakable Kimmy Schmidt was sent to Litchfield, the prison from Orange is the New Black
25.When the guys from Supernatural got sucked into their TV and ended up in an episode of Scooby-Doo, AKA "Scoobynatural".
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