This is a set of 6 cards featuring several shapes. The question What doesn't belong is asked for each one. There are no specific correct answers: all that is required is that students support their answers.
This is excellent practice for determining defining attributes as required in 1.G.1 of the common core.
The uses for this product are endless: whole class discussion, Scoot activities, or warm-ups. However you choose to use it, I'm sure it will help your students as much as it helped mine.