This is the baby version of standard Australian Brilliant Uncirculated coin set for the year. It contains the circulating denominations from $2 down to 5 cents; some of them are in "baby" versions - the $1, the 20 cents and the 5 cents (one of the very few non-circulating 5c coins issued). It has the definitive $2 of the "Aboriginal Elder" type unlike the "regular" sets which contains a coloured (red and black) circulating $2 commemorating the Aboriginal Flag of Australia instead.
The Mint says about it:
"The Royal Australian Mint celebrates the arrival of your newest bundle of joy with its 2021 Uncirculated Baby Coin Set. This uniquely and cutely numismatic set reimagines three of Australia’s distinct circulating coins as gorgeous baby toys.
A posable wooden echidna sits on the 5c, a cute wind-up platypus swims amongst the bubbles on the 20c, while an adorable mob of cuddly plush kangaroos flop about on the back of the $1 coin. Altogether, they create a cute and engaging year set that celebrates the arrival of a new baby, the wonders of a child’s imagination and the simple joys of collecting."