While lots of people have resources available to let you see how transmog gear or even tabards look on your toon, shirts have never commanded quite the same attention. I can understand. They’re understated and, well, largely under-armor, too. But the truth of the matter is, a good (or a bad) shirt can make or break a transmog set.
Thanks be to Wowhead for stepping in to fill the void. They’ve prepared a series of quick links (with images!) by colour to help people easily find what they need.
You can check out their post Best in Show: A Guide to All Shirts here.