Here are a list of prizes that can be unlocked in marketplace events. The prizes for Special Marketplace Events are listed in the Removed, Retired, Truly Limited Items topic. The pics in this topic will be of just the prizes that can only be unlocked in Marketplace Events.
General Marketplace Events
There are 19 different sets of rugs to be unlocked in the market place events.
Marketplace Event Only Prizes
Romantic Sleepwear
Black Grand Piano
Fortune Teller
Rocket Ship Ride
Skate Ramp
Items You May Have Missed Out On
Wedding Dress and Groom's Suit
Baby Decoration Pack
Pet Dragons
Latin Rugs
Infant Overalls
Magical Unicorn Painting
Sleeping Bag Bundle
Hot Tub
Dress-Up Chest for Toddlers
See-Saw
Volleyball Net
Unicorn Rocking Horse
Big-Wheeled Trike
Pet Fairies
Chef Outfit
Exercise Bike
Parrot on a Perch
Patchwork Teddy
Living Teddy Bear
Imperial Barn Owl
Make Out Couch
Wizard Costume Pack
Pop-Up Bookshelf
Home DJ Booth
Campfire Pack
Picnic Basket
Garden Planters
Items Already in the Game
a Time Extension Token
a free Fondue Set
a free Robodog
a free Robocat
a free Samurai Armor
a free Skeleton
a free Dragon Statue
HFN: 22 West Side -- Includes dog and cat Lakeside Christmas Update
I've updated the OP to include a list of all the known marketplace prizes including "items you may have missed out on" and items that are already a part of the game.
HFN: 22 West Side -- Includes dog and cat Lakeside Christmas Update