FrontierVille Collections. You need to complete all the collections to finish the game. This might take a while...
There are at least 37 collections that can be made in the game with everything from wildflowers to snakes. When you have collected enough of each you are prompted to turn them in for a reward. This means that you get more than just gold or XP for a particular activity. You are collecting a nice bonus as well. Complete the horse collection, for example, and you are given a free mule.There is a list of all the things that are collectable here:
You will need to complete all the collections to finish the game. Enjoy!