This app was mentioned in 2 comments, with an average of 2.00 upvotes
I am going to look into this one! I just downloaded Floss Checklist but I don't think it's going to be something that I will like. Thanks so much for the suggestion!
Floss Checklist is 99 cents and has prefilled lists for several different brands, plus a canvas calculator if you need to figure out how much cloth to buy.
My Threads is free, but seems fairly labor intensive to set up. You have to add your colors by number rather than picking from a list.
My favorite pick is XStitcher which is 1.49. For an extra 50 cents you get a lot of the functionality of Floss Checklist, but it also comes with photos of the thread colors for reference, and you can keep separate shopping lists by project.