Group Sites or Social Network Sites. There are usually dedicated sites for different groups depending on what they are doing. Social Networks are much broader, but groups within them like scrapmoms, scrapsisters, and so many more usually share their ideas and projects. It is up to you whether you will join any group if you want to get more details and interact with the people within the group, but you will get templates in there.
Some enthusiasts go out and buy a lot of scrapbooking templates, and that's really fine. But sometimes, you don't feel like going out, or you don't want to spend a little more money for your hobby. That doesn't mean that you should stop scrapbooking, though. You can always go online for your scrapbooking templates, and there are a lot of websites offering beautiful templates for free, so you don't have to pull out your wallet or credit card. All you have to do is download and print them, and you're all set.