When Pokemon first released in 1998, it featured a slightly dark (albeit now classic) commercial where a bus full of Pokemon are compressed into a cartridge of Red and Blue for the Game Boy.
Gold and Silver
The sequels to Red and Blue also featured classic Pokemon art in their commercials as well.
Ruby & Sapphire
The third generation games for Ruby and Sapphire for Game boy Advance also featured another iconic commercial whereby they featured trainers that looked like their pokemon.