In the "Filter" section you will find some photoshop compatible filters and standalone programs for different photo effects and manipulating.
Graphic viewers are really useful for getting an overview of huge picture archives. And if you are looking for decend meta exif editors and viewers. This is the right place to be.
A lot of tools focus a very special task and can provide professional results. Most of them must not fear the comparement with full priced software at all. You will find a bunch of useful all day tools this category.