Useful Free Plugins

those plugins named out are pretty common, some a bit less know could be redprotect wich is a plugin for protecting specific regions (mostly used by players) and quite easy to use but as its less well known, i suggest you have a little tutorial on your server to explain people how to use it. You could also use createyourownmenus plugin wich is very easy to use and gets you a great menu for your server. (you can add commands to items in menu)