(The symbol * indicates updated scans)
Published by Valiant:

Koopa's Health and Beauty Tips
  Family Album "The Early Years"
Dear Princess Toadstool   Another Dear Princess Toadstool (ignore the molester mustache)
From "Meet the Koopa Kids"    

Fins and Roses, featuring Wendy:
Page 1
- Page 2 - Page 3 - Page 4 - Page 5 - Page6 - Page 7 - Page 8 - Page 9 - Page 10

 

SUPER MARIO ADVENTURES series, published in the 1992 Nintendo Power magazines, illustrated by Charlie Nozawa:

Volume No. 1: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8

Volume No. 2: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8

Volume No. 3: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8

Volume No. 4: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8

Volume No. 5: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8

Volume No. 6: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8

Volume No. 7: Page1 - Page 2 - Page 3 - Page 4 - Page 5 - Page 6 - Page 7 - Page 8 (new!)



Scans in Japanese (a.k.a. some of the worst Mario art I've ever seen)

A short strip in Japanese, you figure it out

Another short strip, with Ludwig





Popular pose for the Koopa Kids, it seems.

 

Magazine articles/scans:

These are taken from the April 1992 Nintendo Power magazine. The first one is about what kids would do for a Super Nintendo, the other two are an article about the future of gaming, before Sony decided to split from Nintendo and make the Playstation.

Page 1

Page 2

Page 3

These illustrations are from a comprehensive guide on Mario and Mario World, called Mario Mania. (Submitted by toastypk)

Mario in the Forest of Illusion

Mario at the Twin Bridges