Animal Crossing - There is both a Mario and a Luigi statue, along with code only Super Mario Bros.-related furniture. The game also features the classic Super Mario Bros. games for the Nintendo Entertainment System as unlockable items. There is also two shirts with Mario and Luigi logos on it, as well as the red and green color.
Tetris - Player one is Mario, and player two is Luigi. Also in the ending credits, you will see a few Mario characters dancing and playing music.
Tetris DS - The standard mode theme is from the classic Mario game Super Mario Bros. The puzzle mode theme is from the game Yoshi, and the push mode theme is from Donkey Kong.
Kirby Super Star - While fighting in a ring, you will see Mario, Luigi, Birdo, and Toad cheering you on.
Kirby Super Star Ultra - While fighting King Dedede in the wrestling ring, one is able to see Mario, Luigi, Peach, Wario and two Toads in the audience, and in the Megaton Punch minigame, some Mario items can be found in "The Great Cave Offensive" and when Kirby has the stone ability he can change into a gold Mario statue (note that this is quite rare). Also during the credits for certain modes, when the screen showing "Special Thanks" shows up, a picture of Kirby standing with a golden Mario is seen in a corner.
Pikmin 2 - One of the items that you must take back to your ship is a bottle cap with Bowser on it.
Pikmin 2 - One of the items says Mario Paint on it, the item was blue paint.
Pikmin 2- One of the items you find is called Unspeakable Wonder, and it is in reality Princess Peach's crown.
Brain Age - If you touch the man that is at walking speed, he will whistle the Mario theme.
Call of Duty: Modern Warfare 2 - One of the call-sign emblems in the game is Price (a character from the series) in the form of a Super Mario Bros. sprite.
Picross DS - After completing all the normal mode puzzles, ten Mario-themed puzzles can be unlocked.
Sonic the Hedgehog - In Marble Zone, a pattern on a temple in the background resembles Mario's face.