Craft Knife
A Craft Knife is necessary to make very precise/accurate/exact cuts and can be important when trying to weed out small pieces of paper that get left when making cuts using your Cricut machine. They can also be used to cut materials other than paper that you want to put into your scrapbook projects.

With its razor-sharp edge, piercing tip, and superior blade lock system, Cricut® TrueControl® Knife gives you better control and beautiful results every time. Experience amazing precision and accuracy when working on a wide variety of materials, including paper, cardstock, thin plastics, canvas, and more. You’ll never have to touch a blade with our patented hands-free blade changing system. Thanks to the thoughtful anti-roll design, you can rest assured the knife will stay put when not in use. Get ready to make something amazing because you’ll enjoy hours of fatigue-free work with a comfortable, cushioned grip. Replacement blades sold separately. | Cricut TrueControl Knife | Blue
Here are some pages that I have used my X-acto knife in the creative process: