I’m a firm believer that Myers-Briggs is useful in real life, so why not in your character’s lives? [Full disclosure: I used to be an ENTJ, but since becoming a parent I’ve slid toward ENFJ. Which is fine. The shorthand for ENTJ is “commandant.”] Here’s some more information on using Myers-Briggs in your writing.
And here’s a whole bunch of other links on creating characters.
And if you want to name your characters, a corporation, a vampire, or even a ship, find dozens of name generators here.