I've created a guide to the continuities of Dragon Ball

[The Great Saiyaman]

Ok, here's my take, but be warned: This is about to get real convoluted!

° Future Trunks timeline: Dragon Ball/Z (up until the Freezas arc), Movie 5, Movie 6, the TV Special, episode 191.

° Expanded Toriyama/Toei timeline, where Cell never ever appears: Dragon Ball/Z (since Cell has never arrived, the Z fighters get strong enough and do beat the androids 17-18 on their own), Bardock/Trunks Specials, Movies 7, 8. After Brolys defeat, Future Trunks leaves, strong enough to beat the androids on his own, but is killed by Cell, who steals his time machine and goes to the main timeline (and subsequently dies by Gohan). Movies 10, 11 and 12 also happen, maybe with the Buu storyline attached, but Goku has somehow still died, and not by Cell. How things turned out in regards to Buu and Beerus is unknown.

° Future Trunks timeline number 2, the one in which he dies by Cell. The Future Trunks that returns from the above timeline gets killed by the newly appeared Cell, who steals Trunks' time machine and goes to the above universe, his presence altering/changing the timeline to the following:

° Original Toriyama/Toei timeline: Dragon Ball/Z, Bardock Special, Trunks Special, To! Special. The most straightforward canon, really, with Movie 1 as a loose part of it, due to the Garlic J. arc.

° Expanded Toriyama/Toei timeline: Dragon Ball/Z , the Bardock/Trunks/Yo! Specials, Movies 1, 9, 13, 14, 15, 16. A more expanded version of the previous one, but with explicit extra adventures occuring. 1 has to happen anyway, despite the obvious inconsistencies regarding Gohan, and I find the other adventures add a bit of flavor and are the most continuity-proof entries, too (the 9th could very well explain Vegetas return to training, and the 13th easily fits between the end of the Buu saga and the 14th).

° Gohan beats Buu timeline: Dragon Ball/Z (but Gohan beat Buu there, not Goku and Mr. Satan), Bardock/Trunks, Movies 9, 12.

° The GT timeline: Dragon Ball/Z/GT, Movies 1, 9, 13, Bardock Special, Bardock SSJ Special, Trunks Special, Yo! Special, GT Special.

° The Super timeline: Dragon Ball/Kai/Super, Trunks Special, Movies 9, 13, 16.