There are so many out there, but some are better than others! You will find the sites offering the best ones (because I’m choosy) in The Encyclopedia.
Some templates have been used so often they are hackneyed and others are just plain old.
Others have been put together in such a rush that they are little more than slides with backgrounds. What you need are fully featured templates where the designer has given thought to producing templates with a variety of slide layout designs and where he or she has made conscious choices about colour schemes and fonts…just like they do for the templates that they sell!