People underestimate DBZ way too much. Let's just say this is everyone at the end of the canonical series. If you don't think GT is canon, don't bother arguing. I don't care if you think Akira Toriyama didn't make it. He drew the SSJ4 art and he oversaw the whole production and apparently approved of it. GT is canon in my opinion if you don't like it too bad. OK, end of GT. Let's say this is Goku before absorbing the Dragon Balls, but right after beating Omega Shenron. At full power, in base as an adult, he would already rival the strongest fictional characters. He is pretty much a god at this point and his godly power can get multiplied up to 5,000 times over with SSJ4. The only ones who could oppose him at this point are: Elder God Demonbane, The Living Tribunal, The One Above All and maybe some very few other guys.

Now let's take the strongest non-hypothetical character in DB: SSJ4 Gogeta. He is two godly powers times 5,000 added together and then multiplied by 1,000. He is pretty much top 5 strongest now. Now for hypothetical but possible characters in universe. SSJ4 Vegito is the same as Gogeta but instead when added together their power are multiplied by 14,000. OMG at this point. SSJ4 is not the strongest form. And no I don't mean SSJ5. Just wait.

Let's say Bulma made a cloning machine. She makes a clone of Goku and clone of Vegeta. They take the earring off of Kibito Kai and Old Kai so they now have two sets of Potara Earrings. Fuse one G and V: Gogeta Fuse other G and V with one set of earring: Vegito. Other set of earring fuse Gogeta and Vegito into Gogito.

Gogito in his base could give Living Tirbunal a run for his money because it's Gogeta and Vegito times 14,000. Now imagine...Old Kai...and Gogito. Old Kai does the ritual he did to Gohan...

MYSTIC GOGITO!! You'd think Gogito times 5,000 is omnipotent; SSJ4. Imagine Mystic. Already rivaling Tribunal and Elder God in his base. Then multipliy his power by 100,000 which is equal to Mystic Gogito.

That is all. If you have any ideas for someone who can beat him go ahead and say it. Reality warping and time bending and stuff...pffft. His sheer raw power far exceeds that of the Elder God Demonbane who could beat all the reality warpers easily. This power must give him omnipotent powers, such as warping reality and bending time. Oh and even if they could stop time and hit him or warp reality to pull his molecules apart. He is so invincible and powerful that he would be like what are you doing something? That tickles. Super Buu was able to rip holes in reality and he was 250,000 times weaker than SSJ4 Gogeta who is nothing to Gogito. Not to mention Super Buu was only at 50% when he ripped through the chamber

Go ahead and try to find someone who can even beat End of GT Base Goku. Then we can talk about who can beat Gogito aka no one.