Blessed be the Maximum Threat book, for it's many roll tables, including NPC first names, surnames, positive, negative, and mixed traits, occupations, and way more map hazards. Even if I don't roll on the tables, they're great for inspiration.
I FORGOT IT ADDED A DRAGOON NPC CLASS.
Also the Ramshackle is cool as hell. 15 HP/10 Heat cap, but you can trade HP/Heat (-3 or -2 respectively) to take Features from other NPC classes. It kicks ass.
A lot of the new NPC classes are fun.
The Turret Template solves a problem I had pretty well, and gives some unique types of Turrets. The Fanatic template is great for rushdown, Lazarus for undying enemies that lose the ability to reason after dying once, and the Colossus Template allows you to make an NPC up to SIZE 7