The Neocodex item database statistics are:
Statistics Total items: 40,905 Total priced items: 32,549 (79.57%) Items priced in the last 24 hours: 26,723 (65.33%) Items with owner information: 30,584 (74.77%) Unbuyable items: 3,252 Users currently pricing: 219The total items of 40,905 is 3116 less than Jellyneo's item database which has 44021 items.
It's not a tremendous difference but it is significant.
Jellyneo also has "our database contains information on every item currently in existence on Neopets, including some items that have never been released!" So they do have some extra items.
Anyway, the reason I am pointing this out is to let people know that if you're looking for something and cannot find it then try Jellyneo. If you happen to search for an item that does not appear, please add it to the Neocodex item database.