The rumble pak for the Nintendo DS looks just like a Game Boy Advance cartridge | Did you know the Nintendo DS had a rumble pak? | By DKOldies.com | Alright, So
Help: DS Rumble Pak Not Working : r/NintendoDS
Nintendo DS Rumble Pak NTR-008 (NTR-A-ZV USA) Rare NEW some w/ Metroid Stickers | eBay