Trading/ProfitCalculations

Farmer
Given that crops grow fastest when planted in rows, growing only a single crop is inefficient. So finding the top 2 cash crops is key.

While Beetroot and Wheat have a lower item/Emerald need, the crop yield is insufficient on a per farming tile ratio. Each tile farmed will yield only one food item and a multiple of seeds. While both Carrots and Potatoes will yield 3.43 crops per farm tile on average. Meaning that even with one Carrot/Potato being consumed for reseeding, an average of 2.43 crops are generated per tile. This does not even factor in harvesting using a Fortune enchanted harvesting tool, which will further increase yield with Carrot/Potatoes but not increase yield of crops (only seeds) with Wheat/Beetroot.

Of note: The Poisonous Potato is a bonus item, it is not generated in place of a regular potato

Librarian
Bookshelves can be sold by librarians, which can be destroyed to obtain 3 bookshelves, which then can be used to trade back emeralds if the librarian villager has maxed out discounts, giving you 2 free emeralds.