If the pre-cuts are by Moda, you can see all the fabrics you're buying in a jelly roll or charm pack - not very user friendly site, but at least you can see them.
First, go to
www.unitednotions.com, click on "Fabrics," then "Fabric Collections."
On the next page, you have "Coming Soon," "Collections," and "Basics" - choose whichever tab you want - most of the lines are in the "Collections" tab. You can search to narrow the results and get only a few lines instead of the 500+ results in the main grouping.
Click on the green scissors to download a pdf of all the fabrics or on the blue ones to get jpgs that you can use in Electric Quilt.