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.
Wedding cards should match and have the same design of your wedding theme. The modern and sophisticated way to write the wedding invites is to use a love poem, wedding verse or write something that will match the wedding theme.