The Pink Line
The Cyan LineThe main series. From the 23rd Tenkaichi Budokai, to the 28th Tenkaichi Budokai.
The Red LineThe first point of divergence. In this timeline, Garlic Jr. made his move on world domination between the 23rd TB and the Saiyan arc. This leads to Gohan's power being known to all of the heroes before the Saiyan arc even happens. This drastically alters the Saiyan arc, in which Gohan is a more capable fighter. With a more confident and better trained Gohan, Goku does not get as badly wounded against Vegeta, and is able to embark to Namek with Bulma, Gohan, and Krillin.
Not wanting to deal with Goku and Freeza at the same time, Vegeta opts for a truce with the heroes much sooner, so as to take out the bigger threat (Freeza). Piccolo is (possibly) wished back sooner, due to them being able to gather the Dragon Balls much more quickly. Freeza kills Vegeta, but is himself killed before ever getting the chance to transform, through everyone's combined efforts (with a Taiyoken + Kienzan combo possibly playing a part). The dead heroes are brought back in whatever is the most convenient combination of the two Dragon Ball sets.
Movies 2, 3, and 4 follow from this.
The Lime LineThe "bad" future. Goku dies unexpectedly of a heart virus. Gero's Androids appear out of nowhere and kill all of the heroes except for Gohan. #17 and #18 run amok for quite some time. Babidi finds Buu's ball, but takes it elsewhere, due to there being hardly any life on the planet, let alone enough for Buu's revival. An alternative version of Movie 13 occurs, in which Tapion is killed before Hildegarn gets released, and Trunks receives his sword. Bulma eventually constructs a time machine, and Trunks uses it to travel back in time to give Goku a vaccine for the heart virus, and to warn the heroes of the past of the Android threat.
The Purple LineThe future where Trunks used the shutdown controller to defeat the Androids, but Cell kills him and steals his time machine.
The Green LineThe future where Trunks has RoSaT training under his belt, and he kills the Androids and Cell by his own hand.
The Yellow LineThe timeline where the Coola movies, Movies 5 and 6, occur exactly as depicted. Trunks came back in time in this timeline, and warned of the Androids. The only way for Movie 5 to happen as depicted would be if Goku were to not stay in space long enough to master transforming into a Super Saiyan at will. When Coola showed up, he couldn't just transform, it had to be triggered. The way the fight went lead to Coola being blasted into the sun.
Seeing how helpless they were against a random invader who is supposed to be drastically inferior to the Androids, Piccolo and Kami agree to fuse in order to give them an extra edge. Piccolo here isn't as strong as he is in the main timeline, because he has less training with SSj Goku under his belt at the time of his fusion with Kami. This prompts bringing Dende to Earth to be the new Kami. The Big Gete Star nabs Coola, and Movie 6 happens.
I assume that in all of the other timelines (where Goku learned to become a Super Saiyan at will), Coola still showed up in some capacity, but was more promptly and more fully destroyed. Due to the difference in Goku and Coola's fight in timelines where Goku could become Super Saiyan right off the bat, Coola wouldn't be present for the Big Gete Star to assimilate, causing a butterfly effect where it never went to Namek.
The Blue LineThe timeline where #17 and #18 are defeated by a shutdown controller being built by Bulma from the blueprints found in the ruins of Gero's lab. Movie 7 happens. Trunks returns to his time with the controller (the Lime line), and uses it to defeat the Androids there, only to be killed by Cell.
The Grey LineWhat I refer to as the "Vegeta doesn't ruin everyone's plans" timeline. This one diverges because Vegeta defeats Cell instead of allowing him to become perfect. Cell survives and escapes anyway, though. Goku and Gohan leave the RoSaT early.
After a short break, Movie 8 occurs. It wouldn't occur in timelines where Cell had achieved perfection, as Paragus would have been too wary to meddle with that tier of power. After Movie 8, an altered Plan to Eradicate the [Super] Saiyans happens. Namely, Slug and Tullece can't really be present. Other than that though, it would make enough sense. It would follow Movie 8, as Goku makes reference to Broly.
Eventually, Cell manages to sneak up on #18 and absorb her, achieving perfection. As usual, he announces the Cell Games, gives the heroes 10 days to prepare (which allows Goku and Gohan to finish their training), and leads to Gohan reaching SSj2 and Goku sacrificing himself. After the major timeskip, during the training for the 25th Tenkaichi Budokai, Broly rears his ugly mug again, only to get defeated. Again.
25th Tenkaichi Budokai occurs as normal, with the heroes leaving to go and confront Babidi. Only in this timeline, Vegeta keeps his cool. They swiftly and easily wipe out Babidi and his henchmen, and effectively prevent Buu's revival. Goku's day eventually runs out and he returns to the afterlife (maybe he and Vegeta had their own little fight somewhere, maybe not). With no Buu crisis, things occur as normal after the Budokai, with #18 desiring her payment from Mr. Satan. Movie 11 occurs.
What do you guys think? How would you improve on this? Did I overlook anything that would undermine any of these?The timeline where Ultimate Gohan actually defeated Buu. Goku and Vegeta stay dead. The kids know fusion. Movie 12 can occur. Also makes sense of "base"-looking Gohan one-shotting Freeza (for those who don't think base saiyans ever surpassed Freeza).
Edit #1: Removed/explained the Red Line, and fixed the errors with the Cyan Line.
