If you've been around film/video/audio in any professional capacity for a reasonable amount of time, you know that nothing ever just works. Each device has a seemingly different connector than the last, and you've always got every connector but the one you need. A new section of B&H called Cable Finder can help you find virtually any cable or adapter that they sell on their site. Not only is this great for experienced professionals, but if you've got some less knowledgeable folks trying to buy the right cables, they can look at the photos to determine exactly the cable or adapter they need.
Here's just a portion of the video section:
Most of the sections are mixed and matched with audio cables/connectors and video cables/connectors, but there's a good amount of overlap just in case you aren't sure exactly where a cable or connector would be located. I've run a few film screenings in the past, and I have a bag of cables and connectors that I would bring to each place and for every possible computer or DVD/Blu Ray device, and this site could have saved some time searching for the right cables. There are some specialty and rare connection ends that they list, and it's great to be able to see pictures of the connectors and match up the pins with the cable or adapter you need.
For many out there dealing with people who may not be professionals or aspiring professionals, you can direct your friends/family/relatives to this site and they can decide what they need by looking at the devices they're using and matching up the connectors. Of course, there's no requirement that these cables and adapters be purchased from B&H once you find the right connectors, but their products tend to be from established brands that have great warranties.
Link: B&H Cable Finder
Disclosure: B&H is a No Film School affiliate.