Each set contain a single animal figure, its home, and some accessories, such as food, bows, toys etc. The leaflet with step-by-step assembly instructions includes also an idea picture of an alternative building arrangement. Elements from each series can be all put together, which creates bigger and more sophisticated construction.
In the first three series there were animals representing Heart Lake City fauna (pets and wild creatures). In 2014 a new wave of polybags will contain wild animals from around the world.
In the first three series animals had no individual names stated in the English version of their set descriptions and bios available the friends.lego.com, although it was not a rule for other languages. In the French description of the sets, all the collectible animals from series 1 and series 2 were named.
This series was released in early 2013, although it became available in December 2012.
- All animals included in this series use entirely-new moulds.
- According to LEGO.com, the three are friends and like playing together.
This series was released in April 2013.
- The animals' moulds included in this series appeared earlier in Friends sets. The hedgehog is similar to Oscar but has darker spikes and long eyelashes. The Poodle is similar to the dog from 41007 Pet Parlor but it is wearing a ribbon round its neck instead of a collar and its eyes are green not blue. The Bunny is similar to Daisy but in different colour - grey not white.
This series was released in 2013.
- The fawn is a new mould, while the puppy and parrot are reused moulds in different colours.
- However the collectible animals from this series have no specific names stated in their bios, there are some clues about the identity of the creatures revealed in the quizzes available on friends.lego.com, where the Fawn is called Misty , the Parrot is called Kiki  and the Puppy is called Max .
This series was released in 2014.
- This is the first series to include a creature used in a previous series. The purple turtle called Plum is the successor of the lime unnamed turtle from Series 1. The Tiger and the Penguin are entirely new moulds.
- A yellow bow is now used instead of the azure one.
- This is the first series of sets where animals included have individual names stated in English versions of their bios and set descriptions.
This series is to be released in 2014.
- All animals are new moulds.