On different fansites we can find some information about never used by Cipsoft in game sprites.
According o TibiaWiki.com.br, which for now is the best source in case of this topic we can divide never used sprites in two groups.
1) items that are unused but still exists in Tibia's database:
2) items that are unused and removed from Tibia's database:
It means that there are no plans to implement these items in game anymore.
On the other hand Tibia.Fandom.com presents some additional sprites:
At the time of posting here are some examples of Unused Sprites.
Question Revival II contest - winners! - YakiHon check pleaseFebruary 08, 2021
Third Anniversary InfographicDecember 28, 2020
Looking for a community managerJune 09, 2019