Well I'm going to start off with DBZ (since I don't know much about early Dragon Ball), what would happen if the Z fighters used all their techniques (not just a few and use the others only one time, as well as coming with other plans as well as the glitches in the story line).
 

    Well for starters Gohan would be training with Goku since Goku said that The earth needs Protectors and said that he can still get an education and he's not scared of her because he's the strongest guy in the world. Gohan has a power level of 250 (normal) and 2,500 angry (note I came up with my own set of power levels but to avoid confusion I won't inclued power levels because then everything else will get confusing but I will for when the actual ones are stated). Raditz would come to earth and detect a power level of 580 (goku's beacue he had a training partner) and would then try to Kid nap Gohan but Goku would still lose when Raditz smashes Gohan unconcious and Piccolo would come and after Goku was defeated they would team up (but they would get senzu beans from Korin's tower. Goku and Piccolo would attack Raditz who would still be winning and Goku would power up a Kamehameha wave but Raditz would stop him before he could fully charge Piccolo would use his anntena beam shocking Raditz and Raditz would finally realise that since Goku could use a Kamehameha which could kill him now and Raditz would transform into an Oozaru which he learned how to do by creating the artificial Moon and knocking Goku and Piccolo around in hand to hand combat Raditz would then hit Piccolo and Goku around Goku would fire a Super Kamehameha but Raditz would knock it away and would nearly kill Goku but Gohan would wake up from being knocked out by Raditz (to prevent him from escaping) and would see his father getting beaten and would get pissed and would also see the full moon and would go Oozaru aswell and would not retain his rationality so Raditz would continue pounding Goku into the Ground and Gohan would see his Dad and regonize him and would fire a huge mouth blast at Raditz and would eventualy kill him. Piccolo would destroy the moon and selfishly take a senzu bean for himself, and would heal. Gohan is unconcious and would not know but his Dad had died from the Battle with Raditz. However Vegeta and Nappa heard every word (Goku mentioned the Dragon Balls before being killed while Raditz was beating him) and set a course for earth. Kami tells them and everyone of the Z fighters