Zodiac has a magnet
swinging targets are cool as far back as Gay 90s
Six digit scoring! (you like cleaning score reels? Here's 20 of 'em sucker!)
Fireball has a bunch of cool stuff (multiball, spinning disc, zipper flippers, left kickback and right gate return).
My least favorite "innovation" of all time has to be the roulette wheel. They are usually pointless random awards, slow game play to a crawl, and are used way too much.