This is, quite simply put, one of the best products I've seen on DMs Guild. I've seen plenty of tables to generate merchants (and the stuff that they're carrying), but none have been put together with the obvious care and effort that has gone into this. It's 35 pages of great writing and beautiful art, and it's an excellent addition to any game.
Traders & Merchants contains tables to use in generating any kind of merchant you could possibly think of, from magic item salesmen, spicers, fashion merchants, and even astral travellers with a host of strange magic items. There's a section you can use to generate personalities and characteristics, presented in much the same way as the backgrounds from the Player's Handbook, a ton of charts for loads of different types of merchants of varying levels of wealth and quality, and a really interested section on unique, Legendary Merchants. You'll even find a lot of new magic items in here, some of which are really interesting.
This has already made its way into my game, and I fully recommend you check it out.