I've got a small black box, a few sheets of paper, pencils and dice.
The black box contains cardfiles.




loads of 'em.Whenever I have time i write a few. Shopkeepers, tavern-owners, farmers, street urchins, thieves, bards, barbarians, city guards, merchants, sailors, prostitutes, bards,... anyone you'd meet in a bar, on the streets.
They contain the bare essentials , a short stat block, and a description. Some of 'em contain small plot hooks, a lover lost, involved in something. All of 'em contain something distinctive.
example : fendor turnip farmer. Short man with dirty fingernails, complains in a nasal tone about the different difficulties one runs into when being a full-time agregarian in the turnip business. Hu Com lvl 1 6 HP AC 11 Bab +0 1d6 shovel
This classic example was the horror of my players, who were stuck in a storm for a day and a half in an inn with fendor as their sole companion. Afterwards they had to walk for a day to town, and fendor accompanied them because they were such a fine group of sympathetic young gentlemen, and he was going in the same direction, selling a cartload of turnips.
Basically this was half an evenings worth of fine roleplaying where the paladin had to physically restrain the rogue who was ready to throttle fendor at one more nasal complaint about turnip farming.... Just a random pick from the black box.
Once I have used a card I make another one to keep my stock up, and file the used card by region. You betcharass that when the players are in the area again there will be a rainstorm. You'll never guess who'll open the door when they knock at a farm seeking shelter...... (insert half-mad evil cackle)
Basically this is a very quick way of whipping up general NPC's who populate the towns and cities of my world. I never waste time trying to make up a shopkeeper. If they enter a shop and aren't really keen on roleplaying, the NPC will go back into the box. If they are, and something memorable happens, I write it down on the card and it gets filed. It also makes it easy to slip in important NPC's without giving it away:
GM : you enter a bar. at the table to your left sits a fat merchant with a goatee and a scar across his left han. He wears a golden ring on the pink of his right hand.
Player : anyone else?
GM: aah yes, some other peasants and merchants.
Player : OK. whatever happens, I'm not saying anything to that merchant, we're in over our heads as it is.
GM : but, but...