Truth be told, a lot of this list is going to come directly from the Dragon Ball Heroes franchise, simply because of how completely insane that series is. The video game franchise/spin off series has created some of the most bizarre Akira Toriyama creations that we have ever seen, completely remaking classic heroes and villains in the most "fan fiction" of ways. Debuting as an arcade trading card game, Dragon Ball Heroes has not shied away from creating some of the strangest fusions and new interpretations of old characters.
While Super Dragon Ball Heroes has given fans new villains such as Hearts, bringing back old fallen characters as a resurrected Zamasu, and even diving back into the world of Dragon Ball GT with the return of Super Saiyan 4 Goku, the series has let its characters fall where they may and has never held back on exploring the strangest corners of Toriyama's universe!
Just to kick things off right, what do you get when you combine one of the biggest villains of the Dragon Ball GT series with the villain of the twelfth Dragon Ball Z movie, Fusion Reborn? You get Baby Janemba of course! The personification of evil is now brought to a brand new level as he is possessed by the sword enemy of the Saiyans. If this weren't enough, there's even a version of this where he is a Majin as well.
This all just gets so bizzare at a point guys. So Dark Broly. It's Broly, in Super Saiyan 4 form, wearing an ultra powerful mask called the Time Breaker, while also having one of the Seven Dragon Balls shoved into his chest. At a certain point, you just have to wonder if it is even possible to make a character even MORE powerful, but Dark Broly tries to break the mold here!
We know what you're thinking, you want Cell back. We think that Cell, with all the villains returning in some form or fashion would make for a good addition to the Dragon Ball Super roster, but this version of Cell is definitely a "monkey's paw" scenario. The Dragon Ball Heroes version, Cell X or Cell Xeno, is fused with a Dark Dragon Ball and is given a giant thorax in the process. We have no idea how this version of the second major villain of Dragon Ball Z actually manages to fight anything, but it would surely be something to see!
In Dragon Ball Heroes, Dabura from the latter half of the Dragon Ball Z manages to make a return appearance, threatening our heroes with a power boost all his own. However, much like his initial appearance, he is defeated by Majin Buu who this time around decides to absorb the demon's power into himself, creating the "Dark Demon God Buu" form. If you think this is a lot to handle, we didn't even mention when he fuses with Janemba to boot!
There are in fact several Demon Gods that appear in the Dragon Ball Heroes franchise during the "Dark Demon Realm Saga", but we wanted to focus specifically on this one because his name is Gravy. The Demon God Gravy. That's it. Moving on.
Let's shift over to the hero side of things. If you ever wanted to see some of the crazier fusion ideas brought into anime, than Dragon Ball Heroes is the franchise for you! Gohanks is the result of Future Trunks and Gohan performing the fusion dance and becoming a powerful new being that manages to create an entirely new creation. Considering the sheer amount of insanity that is a part of Heroes, Gohanks is legitimately something we could see happening in the main series some day.
In perhaps the creepiest fusion of the bunch, father and son fuse to become Vegeks, a combination of Vegeta and Trunks thanks to the potarra earrings. Vegeks is created when the father and son pair need a little extra oomph to take down the slew of demon gods that are threatening the universe. Again, this is another fusion that we could see actually happening in the main series.
In Dragon Ball Heroes, EVERYONE can go Super Saiyan 3. It's actually pretty impressive. Vegeta, Trunks, Gohan, Bardock, Broly, everyone. If you don't believe us, we're here to tell you that even Nappa goes Super Saiyan 3, with his beard growing exceptionally long but his hair on the top remaining gone.
The terrifying fusion between Tenshinhan and Yamcha originally appeared in the video game, Dragon Ball Z: Budokai 2, with these two humans managing to pull off the fusion dance and creating Tiencha. While not making any appearances in any anime proper, this crazy combination is worth seeing just for how hilarious the design is.
The Dragon Ball Heroes franchise also managed to bring back some long dead characters, giving them a power boost to keep up with their kin that have far since surpassed them. Such is the case with Xeno King Vegeta, our current Vegeta's father who is brought back to life and fueled by evil energy to act as a counterpart to his son and the rest of the Z Fighters.