Akira Toriyama Had No Part In Filler
A common fan tactic in arguments is to dismiss things one does not like or does not agree with by saying, “Well, the author had nothing to do with that!” When it comes to Dragon Ball, however, the original author’s involvement in supplementary material has been so varied that there is never a clear-cut, one-and-done kind of answer to any given situation.
Akira Toriyama’s initial involvement in Dragon Ball GT is well-documented, with his early character and landscape designs printed and regularly reprinted in sources such as Weekly Shōnen Jump, the Daizenshuu and Dragon Ball GT Perfect File guide books, and general art collections. Daizenshuu 6 (“MOVIES & TV SPECIALS”), in particular, showcases Toriyama’s character designs for the likes of Coola (and his henchmen), movie 7’s Artificial Humans, Broli, Bojack, etc.
What about the general filler material in the television show, though? It can be contradictory, and typically has (debatably) less-than-stellar attempts at storytelling. Toriyama had nothing to do with any of that, right…? Not quite.
It is certainly not the case that Toriyama “wrote” and “drew” every single episode in the television series (he is a manga author and artist, after all), but the 2003 anime guide Son Gokū Densetsu gives us a little glimpse into the clearly-overworked man’s involvement in the television series.
There were many character designs Toriyama came up with for filler material, including Paikuhan, Dai-Kaiō, and the beginnings of King Vegeta. We also learn that for many story points, Toriyama would typically come up with a vague idea and leave a memo for the television series staff to — essentially — go wild with and develop a full story from said idea. Some of these items included the back-history of the Saiyans and the Tsufruians for Dragon Ball Z episode 20, the Z-Warriors’ training with the “Illusion” Saiyans via God’s Palace, and Lunch’s persistent chasing of Tenshinhan. Even Yamcha’s job as a baseball player was Toriyama’s idea!
Also remember cases such as Bardock, where the original television special’s storyline was crafted by Takao Koyama and character designs were essentially a joint-collaboration between Akira Toriyama and Katsuyoshi Nakatsuru. It turned out that Toriyama liked the idea so much, he ended up integrating a cameo from it into his own storyline in the manga… before completely redoing and reintegrating that story as “Dragon Ball Minus” in 2014, followed by significant updates during the Dragon Ball Super manga’s “Granolla the Survivor” story arc in the 2020s!
(Just post-2009 alone, Toriyama’s involvement in the franchise has been simultaneously more, less, increasingly varied, and conservative — all at the same time! — compared to his work before!)
“Filler” material for television series adaptations is something that original authors are generally given the option to consult on, and in the case of Dragon Ball, there are certainly confirmed, explicit, documented cases of Akira Toriyama’s involvement. Whether or not you want to have the larger conversation about their canonicity status… woof, you’re on your own there. Godspeed.