Right now there are six types of crops you can farm, more could be added, so who knows how many more types of seeds there will be. As of the March 2020 update, three new seeds where added to the shop.
You can find the seeds in Loot Boxes and in the RPG Shop. Right now, Bean, Coffee and Corn seeds are not in Loot Boxes. Also Coffee seeds can only be bought weekly.
Seeds are found on page 1 of your inventory [nya!rpg inv] or [nya!rpg inv seed].
While farming you will use a lot of Stamina, so you need to keep your eyes on it.
|Bean||nya!rpg farm bean|
|Beetroot||nya!rpg farm beetroot|
|Coffee||nya!rpg farm coffee|
|Corn||nya!rpg farm coffee|
|Potato||nya!rpg farm potato|
|Pumpkin||nya!rpg farm pumpkin|
|Rice||nya!rpg farm rice|
|Watermelon||nya!rpg farm watermelon|
|Wheat||nya!rpg farm wheat|