Please search before making a thread. This should help you get started though: http://community.playstarbound.com/resources/unofficial-modding-ebook.2930/ Edit: Seeing how OP changed his comment from wanting help creating a mod to wanting 'cool mods' , this reply sure seems like a strange answer.
That is easy. It's a steo-by-steo tutorial into the very basics of modding Starbound. Compared to other games which require programming knowledge, modding Starbound is easy as heck to mod if you have a modicum of patience.
Yep, I'm pretty sure this thread has been totally derailed. Either it needs to get shut down, or back on topic.
Calm down and stay on topic, please. If you're just looking for mods to download, all you need to do is say so. http://community.playstarbound.com/forums/mod-releases-wips.103/