Here's a categorised list of resources, with contact web links.
You'll find many more in "Webpedia" in the Webskel book "Nuts and Bolts of Internet Business."
Disclaimer: WebSkel has no affiliation or commercial agreement, other than as a user, to any of the companies mentioned here. Also not all the resources have been tested by WebSkel, therefore you should test them out before use.
There are, of course, many other add-ons available from the web. Another link to finding resources is http://www.findsticky.com. If any of these add-on accessories seem useful, then please try them out. Most of them just require you to copy and paste HTML code onto your page. In general all the accessories I have tried worked as described, but occasionally you may need to modify one slightly. So try first!
