Bonus are featured in several tankōbon volumes of the Dr. Slump manga. Those are cards, short documentaries, or games.
Hoyoyo cards (Volume 1)
Volume 1 features seven collectible Hoyoyo cards, which have to be cut from the manga pages.
Volume 2 BonusesVolume 2 features a "color me" page with the cover of said volume, a tip on enlarging pictures with a grid, the drawn materials Akira Toriyama uses to create his manga, a bird eye's view of his room drawn and a "fault finder" with over 30 differences between both images.
This Is How I Draw Dr. Slump, Y'all! (Volume 3)Main article: This Is How I Draw Dr. Slump, Y'all!
Scattered in volume 3, are the pages of a short manga documentary about the process of how Akira Toriyama gets each chapter of the Dr. Slump manga done. There is also a bonus maze and tutorial to making a soldier hat.
Dr. Slump Ho-yo-yo Resume (Volume 4)
Volume 4 features the Penguin Village ID cards of various characters of the series. (Note that Arale's features a mistranslation: it should read "3rd of Flying Fish, 1967", which is part of her cover story; she was completed on the same date in 1980. Her age being given as "14", however, is a mistake on Akira Toriyama's part, perhaps because he had not yet decided which sea-creature corresponded to each month; she should still be "13" as of April 1st, 1981.) There is also 2 bonus heads and a fault finder of the fourth volume's cover which has 10 differences and also serves as a "Color me" page. .
Me Back Then (Volume 5)Volume 5 features several short manga documentaries about Akira Toriyama's past, a special insert of Arale's very own short manga and a King Nikochan pinup.
Volume 6 BonusesVolume 6 features various little bonus games/activities and miscellaneous bonuses such as a cassette tape label.
Me Back Then Redux/Dr. Slump Super Quiz (Volume 7)Volume 7 features a few short manga documentaries about the author's past, a continuation of the bonuses from Volume 5. It also has various Dr. Slump Super Quizzes of growing difficulty (from Daycare to Penguin Imperial Co, Ltd.) and a Dress-me Nikochan.
"I'm Number One!" Contest (Volume 8)Volume 8 features the "I'm Number One!" contest with categories such as coolest, dumbest and ridiculous. Readers from Japan submitted their votes when Dr. Slump was still serializing in Weekly Shōnen Jump. There's also an intermission during Penguin Gran Prix, Part 3 called "The Palm Tree Moveth" which is a 2 page non-fiction manga story involving Akira Toriyama and his editor getting into a situation during their vacation.
Character Creation/Dumiyamma Daily (Volume 9)
Volume 9 features short stories about the creation of a few characters in Dr. Slump and articles of the Dummiyamma Daily, dumb stories personal to Akira Toriyama.
Penguin Village Guinness Book (Volume 10)
One day with Akira Toriyama (Volume 12)
A photo documentary that shows Akira Toriyama's typical working day in 1983. It includes the author's comments.
Hall of Shame (Volume 13)
Me and The World (Volume 14)
Me, Then (Volume 15)
The Secrets of... Dr. Slump (Volume 16)
Board creation (Volume 17)
In the pages of Dr. Slump volume 17, Akira Toriyama explains how he creates boards for his manga, with a board from Dragon Ball as an example.
So It's Finally Over Doctor Slump (Volume 18)
Various games and manual activities are featured in the pages of the Dr. Slump manga.