how do i find plugins that are compatible with WP 3.1.2

I am using 3.1.2 to set up my first blog. All is well except I want to re-order my categories. A plugin search shows many plugins but none I researched are for this version of WP. I don’t want to trash my work by using an unsuitable plugin. So two questions:

1. Is there a category re-ordering plugin for WP 3.1

2. More generally, how do I find plugins that are good for this version?

Many thanks