The answer is a simple "no"
if the themes/templates are your own work.
If you are distributing anything created by other people/companies, you would need to have permission (a license) to redistribute. If the themes/templates are derivative of other work, then you would need permission (a license) to create derivative works and distribute them. Things that are released under "copyleft" (like the GPL and LGPL) or under more permissive licenses (MIT, Apache, BSD) ought to be okay. Remember that you also need permission to use any graphics, wordmarks or trademarks you incorporate into and/or distribute with the themes/templates. You would need to
post the license under which you are using any resources clearly on your site, and that license needs to be verifiable. If the license requires attribution (most do), then you also need to post the attribution. And the license under which you release works has to conform to the license under which you obtained it; GPLed works need to be released under the GPL and so on.
For third-party works, it's generally safer to simply link to the original source rather than to host the files for download. Not only does it save you server space and potential copyright difficulties, it makes the original author happy.
If your "own work" is clearly derived from a site that guards its design (which can be a trademark, "trade dress" or a design patent), or if they are designed to confuse visitors for fraudulent purposes (looking like, say, Facebook if you don't look too closely), then you can expect to be suspended even if it's otherwise a
clean room implementation. Trivial similarities or obvious arrangements (using the standard "container", "header", "nav", "main" and "footer" IDs for divs on a page, for instance) won't be an issue -- there are things that are considered standard practice.
The same thing applies to any font resources you may be using. As a creator, you can generally
use the fonts you have licensed (in a graphic, say) but you may not be allowed to include the font as a file set for use in CSS (or even embedded in a documentation PDF).
