Very sad news. The list of games Iwata-san worked on or oversaw is astonishing. Animal Crossing, Super Smash Bros, Metroid Prime, Earthbound, Super Mario Sunshine, WarioWare, Eternal Darkness, so many Kirby and Pokémon games, and dozens more. Plus he ran Nintendo during the ridiculously successful Nintendo DS and Wii eras.
This article is a nice collection of memories and thoughts from so many in the gaming industry. (And too many drawings of Sad Mario, but that was to be expected.)