Harvesting buildings can pull resources directly from the game. Their output depends on their employment % and building level. These buildings are easy to manage and often have secondary functions such as Happiness bonuses. Unlike processing and Crafting buildings, Harvesting functions are never duplicated in high ranking / main buildings.
Farms - Farms are your very first Harvesting building. They are constructed with Grain and even if you throw away all your starter Grain, it is possible to use actions to produce enough for your first Farm. After that, any one Farm can produce more than enough Grain to maintain itself and many other Farms. Farms also harvest Flax, Hemp, Produce and Herbs. The importance of Farms stems from it's wide variety of resources. Flax is processes into fine Linen. Hemp is a construction material and processes into Canvas as well. Both Produce and their result Groceries are necessary to grow your NPC populace. Herbs and their result Tinctures are both good for magic and Health. Finally, Grain can be processed into both Bread and Beer, which are usually in high demand.
Fishing Piers - The Fishing Pier is your only building source for aquatic resources. This handy establishment pulls Fish, Mollusks and Oysters out of the ocean. Having them in your district will provide a small local Health bonus. Fishing Piers require Lumber to build and maintain, meaning you'll need to have built a Logging Camp to maintain them. This building pairs with the Fishery, which processes all three types of resource. Fish can be eaten as is or process into delicious Fillets. Mollusks become Dyes, necessary for art and paperwork. Oysters can be eaten or processed into either Pearls or Black Pearls.
Hunting Camps - Hunting Camps can be built anywhere and require only Hemp to construct. This makes them easy to construct with only a Farm infrastructure. These light-weight buildings produce a steady output of Game or Pelts based on employment and building level. Hunting Camps have no happiness effect and require no prerequisite research. Game can be eaten on it's own or processed into Meat in a Butcher Shop. It is associated with Lord meal bonuses. Pelts are processed into Furs, used in gear crafting.
Logging Camps - Logging Camps can only be built in the Forest Outpost and are your only steady source of Lumber. They also produce Pulp for Paper which may seem trivial in lower ranks but quickly grows in demand as your city requires more and more paperwork. Lumber is useful on it's own as a construction material and also can be processed into Boards, an even more popular construction material. Building and upgrading your Logging Camps requires a supply of Hemp.
Quarries - Quarries are another Hemp-based harvesting building and can be built in any district. These valuable holes in the ground can harvest one of six earthy resources. Quarries can harvest Ldoestone, Marble, Raw Gems, Sand or Sandstone. Lodestone is a magical reagent and can be processed into Magnets. Marble is a fine building material that can be carved into Slabs in a Stonecutter and similar buildings. Raw Gems are valued by the Faeries and can be processed into Cut Gems in the Jewelcutter. Sand becomes Glass in the Glassblowers and Sandstone can either be used to construct simple buildings or processed into highly valued Bricks in Brickmakers and many main buildings.
Mineral Mines - The Mineral Mines can only be built in the Mines district and require a supply of Livestock to construct and upkeep. Each Mineral Mine can harvest one five options. The mines produce Nickel Ore, Gold Ore, Copper Ore, Pig Iron and Silver Ore. The Mint and Mint-like buildings process Gold Ore into Gold Florins, Silver Ore into Silver Thalers and Copper Ore into Bronze Litra. Foundries and Foundry-like buildings produce Pig Iron into Iron Ingots and Nickel ore into Steel Ingots.
Vineyards - The Vineyards are not limited to any one district but are somewhat challenging to build early on because they require Boards (along with Flax) to build, upkeep and upgrade. These valuable harvesting buildings produce both Grapes and Olives, which in turn are processed into high-value goods. The Winery and the Grand Pavilion are the only buildings that process Grapes into Wine. The Oil Press, Main Street and Sewage Pipes all process Olives into Oil. Vineyards each provide a fairly powerful local Health bonus to their district.
Pastures - Pastures are the only harvesting building that has prerequisite research. In order to build Pastures, you must first research Science, then Biology then Agriculture and finally Pastures themselves. Construction materials include Grain and Fillets. While this may be a pain, the Pastures are also your only reliable source of Animals, Fledglings and Livestock. Animals can be processed into either Familiars in Alchemy Shops or Hounds in Kennels. Once they are Hounds, they can be crafted into Hound companions. Fledglings are processed into Pet Birds in Pet Shops and from there can be crafted into Songbird companions. Livestock is the most powerful product of the Pastures. They can be processed into Leather, Wool, Meat, Horses and Pack Animals. Both Horses and Pack Animals can also be crafted into companions.
Orchards - Orchards must be built, upgraded and maintained with Fillets. They can only be built in the Inner Courtyard and provide a settlement-wide Health bonus. Each level of Orchard can store several Carts as well as harvesting Olives and produce. The Orchards doesn't exclusively produce anything, but they are cheaper than Vineyards to build as a source of Olives.