EDIT: This no longer works. The Devs have removed almost every item listed here from the auction search results. I wonder if this topic prompted the sudden house cleaning?
I believe that the auto predict on the auction search is maybe "too good".If you type a single letter in to the auction search box it will list every item in (and more interestingly not in) the game that begins with that letter. Well every item that is able to be auctioned. I know most of you know this, but I'm am sure that there are many people who don't. The following is a list of items that are not currently available in the game:
Abstraction
Admin Widget (Starman for the win)
Anxiety
Apple Juice
Apprehension
Ayn Rand Doll
apple seed (Apple trees?)
Basic Sno Cone (maybe at one time we were going to be able to flavor our own)
Billionaire's Bacon
Bummer
Bunch of Crushed Hellish Grapes
Bunch of Crushed Hellish Grapes (It comes up twice)
Butter
Butterfly Net
Christmas tree ornament (Most likely a seasonal item)
Coin
Concept
Consideration
Construction Tool
Contemplation
Currant
cal test object
Dead Piggy ( 0_0 Oh my!)
Desire
Durian
Egg Carton (Perhaps like a "bundle" option for eggs)
Ennui
Fancy Cheese
Feeling
Figment
Fireworks (Most likely a seasonal item)
Fried Goat's Ear
Friedrich Nietzsche Doll
fried eggs DELETE ME
Gas
Goat Arse
Goat Liquer
Goat eye
Golden Egg (Most likely a seasonal item)
Grain Seed (Guess before chickens made grain?)
Green Leaf (Maybe became Spinach?)
Green Leaf Seed
Hope
Ideal
Image
Inkling
Jamon Bellota
Juicer
Juju Shoo-Shoo Powder
Kaysadillah
Letter Block A
Letter Block B
Letter Block E
Letter Block M
Letter Block S
Letter Block T
Ludwig Wittgenstein Doll
Meditation
Memory
Mirage
Miso Mayo Japadog
Mortar and Pestle (Became the Grinder)
Mountain Oyster
Musicblock T-1
Musing
magic apple
Notion
Ocean Oyster
Okonomi Japadog
Paper Plane
Party Pack
Pebble
Pepper (Replaced by Black Pepper)
Perception
Platypus milk
Power Cell
Prairie Oyster
Prairie oyster pearl
Prune of Longing
pen (Replaced by Quill)
Radish
Radish Seed
Rasher of Bacon
Raw Goat Arm
Reverie
Rocket
Rumination
Sack of Plant Feed
School Diploma
Sheep red wine
Sheep-Ass Vodka
Small Seed
Small brown seed
Spotted Guava
smoothie
Theory
Thimble berry
Thought
Tuna Berry
Turnip
Turnip Seed
Vole Milk
W Bolognese Sauce (Became Wicked Bolognese Sauce)
Whale Milk
Worry
Many of those items have a ? for their picture, but a lot of the have some really cool icons.