Custom lists allow you to make your own list in an order you specify.
The list is created by putting a list of item ids seperated by commas as a URL argument. Item ids are found by searching and looking at the number in the URL
You may also add a title to describe it.
These lists are sharable, all you have to do is send people the URL and to save it, add it as a bookmark.
Example: http://www.gw2tp.com/custom-list?name=Cloth&ids=19720,19747,19740