Manata.net's NPC Generator
When I need a basic character sheet for a 5th edition Dungeons and Dragons NPC, this is the place I go. When you need a new character simply refresh the page. The page can easily be printed out and look pretty, and definitely highlights the different aspects to make your character unique and guide you in how to roleplay them.
This one is so simple, there is no point in saying much about it. What you see is what you get.
DMTools.org has many different generators and lists. Much of the content is built around an earlier edition, so may not be helpful for Fifth Edition Master of Dungeons like myself.
A lot of the generic stuff is so good that it makes up for the older edition. I particularly like the Benign encounters generator. It can help you create a roleplaying experience when your session is stagnating. Also good are the Demiplane, Towns, Mercenary Jobs, and PC/NPC generators.
I would stay away from anything with stat block, or any of the items. These items and monsters will not balance well with fifth edition, and there are better examples of them anyway in the previous articles about Online Tools linked at the beginning of this article.
Thieves Guild Riddle GeneratorI love when I find an online tool that is completely different from any of the online tools I've used before. This one doesn't do NPCs, towns, cities, or monsters. It is purely for generating riddles.
Have you ever tried to think of a riddle for your players? It is exceptionally hard to do, at least for me. Even if you can think of a riddle, it is difficult to tell if the riddle makes sense, or can be easily solved without testing it. The Thieves Guild Riddle Generator completely solves this problem by giving you riddles and their solutions. Your time is better spent prepping for your games in other ways. A good Master of Dungeons has to be a cartographer, author, party planner, actor/improviser and director. Why should they have to become the riddler too?
If you are interested in more useful online tools, check out the previous 3 blog posts (first, second, and third). Also, the Master of Dungeons Non-Combat Magical Items Deck is sort of like a generator, as you can use it to get a random magical item, you can get it online as well and I think it would be a great present for yourself, or any other Master of Dungeons in your life. (Plus it would support this humble blog).
I hope you love all these tools as much as I do, if you haven't already make sure to follow Master Of Dungeons blog on all of the relevant social media (Google Plus, Facebook, and Twitter), where I post all updates to the blog, as well as interesting things I find around the internet related to D&D and RPGs.