Crossovers you would love to see happen

Dbz and DBZA,make it an April fools thing or something.

Mst3k and Star Trek,that would also be funny.

Also all the cancelled OK KO Crossovers

I'd love to see a true, official crossover Super Mario Bros./Sonic The Hedgehog game, not just the various Smash Bros. appearances, or the Mario & Sonic At The Olympics series.

I also would love to see a crossover with Ultraman, Kamen Rider, Super Sentai, and Godzilla. Japan's 4 biggest franchises and tokusaku and Kaiju series, all in one big epic event.

Digimon Adventure and classic model era Thomas The Tank Engine

Cardcaptor Sakura and Sailor Moon

Grade School era me would've marked hard for both of those back in the day.

KND and Craig of the Creek

Another JJBA 1-6 x JJBA 7-8 crossover (Eyes of Heaven was the first one)

Dragon Ball Super and Dragon Ball GT

A Cartoon Network crossover like never before. Characters from every series coming together, with all of them playing a part. It would bring back people who worked on all these cartoons. 

Kratos and Asura crossover. Imagine if there was a multiverse that consisted of god killing characters that do not belong to other multiverses (Sorry Marvel and DC fans).

I probably have way more that I cannot think of.

Duke Nukem and Tomb Raider(or Uncharted of course).

I also would like to see a crossover with Regular Show and The Amazing World of Gumball.