Most likely the best place to start is DMOZ directory.
Look for content providers in adult DMOZ.
Other places to look for would be adult link sites.
Many link sites offer seperate section for adult webmasters, look for Webmasters links.
You could try search engines also. Even again, if you have done it some time ago.
Search engine might offer new results today.
Try to give detailed description what you are looking for.
Searches like "content" would not give good results,
but "adult video content" (with double quotes!) can give much better results.
If you are looking for specific type of content, include that also in search.
For example "adult lingerie video content" and "adult bdsm video content" can
give quite different kind of results.
