Items you find in Palia can have a 
Quality marking. This means, for example, that a dish you cook with Quality ingredients will give more Focus, or that the item will sell for more gold.
Bugs
Differences in catch rates can currently be found here.
Differences in sell prices can currently be found here.
Fish
Differences in sell prices can be found here.
From the Palia wiki's Star Quality page, reformatted for Palia Pal. Text available under CC BY-SA 4.0.