FamilySearch certifies a number of different programs, including different types of programs, that work with FamilySearch.org's Family Tree program. Essentially these programs share data back and forth with Family Tree at differing levels. To find a list of these Certified Programs, go to the bottom of the FamilySearch.org startup page. Here is a screenshot of the bottom of the page with an arrow showing the link labeled "About."
This link takes you to following page where you need to click further on the "Products" link. Here is a screenshot of that link:
The Products page has recently been redesigned. Presently, it looks like the following screenshot:
Clicking on each of the icons takes you to an individual page telling about the specific product. There are changes to these pages frequently and not all of the products have been discussed or reviewed. The various levels of Certification used to be explained, but that explanation, along with the tiny icons, has disappeared. I suspect these pages are in transition and will change again soon.