Werewolves (perhaps a game pack focused on Native Americans/lunar phases)
Fairies (maybe a game pack focused on collecting, hoarding, antiquing)
An actual, permanent plant sim (should have come with seasons)
Cars (update and kit)
Elder Stuff (could be a cool stuff pack with some 60s influence)
Teen Stuff (stuff pack a lot of people want)
More Hobbies
Bands (could come with poetry, rap, instruments, tattoos, piercings)
Royalty Game Pack
Horses/Unicorn (Maybe a kit)
Theme park
Attraction system/astrology (should have come with My Wedding Stuff)
Vacation expansion (Al Simhara, Champs Le Sims, whatever else)
a Sixam world
an African world
a Future themed game pack