Nintendo 3DS

[Woppet*]

The rumble pack wasn't used in nearly enough games. It made PiT so much better.

Quite a few games use it actually.
I've got an easyflash 3 in 1 with a rumble pack in at all times when i play my flashcart, every now and then you come across a game that uses rumble.

Air Traffic Chaos
Akagawa Jirou Mystery: Yasoukyoku
Animal Boxing
Bomberman 2 (Custom Battler Bomberman in Japan)
Club House Games (42 All-Time Classics in Europe)
Custom Robo Arena
Daigasso! Band Brothers DX
Diddy Kong Racing DS
Dirt 2
Elite Beat Agents
Ferrari Challenge
GRID
Hotel Dusk: Room 215
Higurashi no Naku koro ni Kizuna: Dai-Ichi-Kan - Tatari
Higurashi no Naku koro ni Kizuna: Dai-Ni-Kan - Sou
Higurashi no Naku koro ni Kizuna: Dai-San-Kan - Rasen
Iron Man
Juiced 2: Hot Import Nights
Magnetica (Actionloop in Europe)
Mahjong Fight Club DS: Wi-Fi Taiou
Mario & Luigi: Partners in Time
Mario & Luigi: Bowser's Inside Story (Feature removed from US version)
Metroid Prime Hunters
Metroid Prime Pinball (Rumble Pak came with US version)
Moon
Need For Speed: Undercover
Need For Speed: Nitro
Moero! Nekketsu Rhythm Damashii: Osu! Tatakae! Ouendan 2
Orcs & Elves
Picross DS
Power Pro Kun Pocket 9
Power Pro Kun Pocket 10
Professional Fisherman's Tour: Northern Hemisphere
Puyo Puyo! 15th Anniversary
Race Driver: Create and Race
Sega Superstars Tennis
Space Invaders Extreme
Space Invaders Extreme 2
Star Fox Command
Star Trek: Tactical Assault
Super Princess Peach
The Legend of Spyro: A New Beginning
Theta
Tomb Raider: Underworld
TrackMania DS
Treasure Gaust: Gaust Diver (Deep Purple)
Treasure Gaust: Gaust Diver (Crimson Red)
V8 SuperCars Australia 3
Viva Piñata: Pocket Paradise
Wario: Master of Disguise
Wild West, The
WWE SmackDown vs. Raw 2008

That's quite a lot really considering not that many people have a rumble pack.