We'll, The Powerpuff Girls will meet The Teen Titans! So, after that, more crossovers could be possible!
My hope is...
SpongeBob SquarePants:
SpongeBob would be a closest guess in my opinion, Beast Boy and Cyborg are like SpongeBob and Patrick, and Raven and Mr. Krabs are though!
What are your hopes for a next crossover after Heroes Vs. Heroes?