Here is the full list of all 16 I commissioned some cats 3 achievements.
Complete the game in its entirety.
Find everything hidden in the Mountain Temple artwork.
Find everything hidden in the The Corner Store artwork.
Find everything hidden in the Forgotten Library artwork.
Find everything hidden in the Big Pipe Machine artwork.
Find everything hidden in the Peaceful Alleyway artwork.
Find everything hidden in the Stripy Planting artwork.
Find everything hidden in the The Viking Ship artwork.
Find everything hidden in the Mechanical Plasma Generator artwork.
Find everything hidden in the Pizza and Tidying artwork.
Find everything hidden in the City and Cruise artwork.
Find everything hidden in the Lost Travellers artwork.
Find everything hidden in the Bunny Lady artwork.
Find everything hidden in the Hidden Hillside House artwork.
Find everything hidden in the Panda Checkers artwork.
Find everything hidden in the Unkempt Gated Mansion artwork.