Mario has graced many a Nintendo Power cover, and there are even more NP volumes that cover Mario games. However, the collection here stops at the covers.

Covers

(Some of my copies are really beat-up. If anyone can provide better scans, we'll use them.)

• July/August 1988 (first issue) - Super Mario Bros. 2
• March/April 1990 - Super Mario Bros. 3
• Vol. SG1/NP13 - Super Mario Bros. 3 Strategy Guide
• Vol. 18 - Dr. Mario
• Vol. 28 - Super Mario World
• Vol. 39 - Mario Paint
• Vol. 41 - Super Mario Kart
• Vol. 52 - Super Mario All-Stars
• Vol. 58 - Wario Land: Super Mario Land 3
• Vol. 61 - GB Donkey Kong
• Vol. 77 - Super Mario World 2: Yoshi's Island
• Vol. 82 - Super Mario RPG: Legend of the Seven Stars
• Vol. 85 - Super Mario 64
• Vol. 86 - Mario, Bowser et al.
• Vol. 87 - Tetris Attack
• Vol. 88 - Super Mario 64 [front | back]
• Vol. 93 - Mario Kart 64
• Vol. 100 - Super Mario 64 [front | back]
• Vol. 104 - Yoshi's Story [front | back (subscribers only)]
• Vol. 117 - Mario Party
• Vol. 128 - Mario Party 2
• Vol. 135 - Mario Tennis
• Vol. 141 - Paper Mario
• Vol. 143 - Game Boy Advance playing Super Mario Advance
• Vol. 145 - Super Mario Advance
• Vol. 148 - Mario Kart: Super Circuit
• Vol. 150 - Luigi's Mansion
• Vol. 151 - Super Smash Bros. Melee
• Vol. 160 - Super Mario Sunshine
• Nintendo Power Advance Vol. 1 - Super Mario Advance
• Nintendo Power Advance Vol. 2 - Mario Kart: Super Circuit
• Nintendo Power Advance Vol. 3 - Wario Land 4
• Nintendo Power Advance Vol. 4 - Super Mario World: Super Mario Advance 2

Comics

• Howard & Nester (May/June 1990)
  
  Howard (Phillips) and Nester (NP mascot?) were involved in various hijinks during the early years of Nintendo Power. In this particular issue, H&N go inside Super Mario Bros. 3.
• Super Mario Adventures (Vol. 32 - 43)
  This comic was illustrated by Charlie Nozawa, and spanned a year of Nintendo Power issues. Later on, Nintendo published a collection of all the SMA comics.
• Mario Vs. Wario (Vol. 44)
• Mario VS Wario (Vol. 56)

Player's guides

(Some of my copies are really beat-up. If anyone can provide better scans, we'll use them.)

• Game Boy (covers Super Mario Land and Dr. Mario)
• Mario Kart 64
• Mario Mania (covers Super Mario World)
• Mario Paint
• NES Game Atlas (covers Super Mario Bros. 1, 2, 3)
• Paper Mario
• Super Game Boy (features Super Mario Land 1, 2, 3, Dr. Mario, Yoshi, and GB Donkey Kong)
• Super Mario 64
• Super Mario All-Stars
• Super Mario Bros. 2 Inside Out [part I | part II] (pull-out tip books)
• Super Mario Bros. 3 ("Strategy Guide 1 / Nintendo Power 13")
• Super Mario RPG: Legend of the Seven Stars
• Super Mario World 2: Yoshi's Island [front | back]
• Super NES (covers Super Mario World)
• Super Smash Bros. Melee
• Yoshi's Story