Exactly what the title says and here's the crossover ensembles that this poll presents:

  1. Sora, Riku, Kairi, Donald, and Goofy (Kingdom Hearts); Ash, Misty, Tracey, and Melody (Pokemon); Taichi, Yamato, Sora, Mimi, Koshiro, Joe, Takeru, and Hikari (Digimon); and Robin, Starfire, Beast Boy, and Raven (Teen Titans) where the specifics are: 8 Original Digidestined are takes 02 forms with Summer Clothes, KH Humans takes KH2 forms, both Ash and Misty are wears their Advanced Generation clothes while Melody wears her street clothes, and so on(including the Teen Titans are must from 2003-2006 cartoon instead of today's TTG). and to make everything fair, at least some of the characters here are deliberately powered up to makes everyone in this crossover ensembles can fights in (near) equal terms
  2. Anyone from Warhammer 40.000 with whole bunch of Happy Tree Friends, Mario series, Sonic the Hedgehog series, and My Little Pony: Friendship Is Magic main characters
  3. Sylar from Heroes and Flippy from Happy Tree Friends
  4. Marco, Tarma, Eri, and Fio from Metal Slug with Any FPS main character like Doomguy or Master Chief
  5. Eduardo Rivera, Kylie Griffin, Garrett Miller, and Roland Jackson from Extreme Ghostbusters with Rick O'Connell, Evelyn O'Connell, Jonathan Carnahan, and Alex O'Connell from The Mummy Trilogy
  6. Isami Hanaoka, Soshi Yukimi, and Toshi Tsukikage from Soar High! Isami with Recca Hanabishi, Domon Ishijama, Fuko Kirisawa, Tokiya Mikagami, and Kaoru Koganei from Flame of Recca
  7. Mystery inc from Scooby Doo franchise with Team Fortress 2 mercenaries
  8. Adam Jensen and Avatar Korra: the former are fully augmented and can add extra tech to his augs while latter can access Super Saiyan powers through Avatar State(the whole reason it's referred as Super Saiyan powers are same with Super forms of Mobians with Chaos Emeralds are referred as one)
  9. Sheldon J. Plankton from Spongebob with Computer-Assisted and Biologically-augmentd lifeform from Command and Conquer
  10. Grox from Spore and Sermeg Oguma from Metal Slug 3d