So where do you get your pregenerated materials from? It seems I've been a little out of touch. Any help? Specifically I am looking for quick and easy to use NPC's

Take your player's sheets so it's always balanced. Just don't tell them

Also a little obvious. My players are too clever for me to rely on that sort of thing more than once. I have all the PDF's, so for now I snagged some of the as written NPC's. Knowing my players, I'll likely need to add twice as many as I think I need. Clever bastards.

When improvising NPCs on the fly, I often do them like spirits: they have attributes and skills based on their profession rating, and any thematically fitting equipment.

E.g.: A squad of Go-Gangers (R3): All 3s in their stats, 3s in their skills, no ware, lined coat, a simple gun (Ares Predator, Remington 990 or similar), some Cram/Jazz, other paraphernalia needed to function (comlink etc.)

Only works in the range of rating 3-6, though.

PACKS by Ancient History?

Is there any difference between the one posted on these boards and the retail one in Runner's Toolkit?

Yeah, I believe there is, if only for copyright reasons.
It's not like I've had time or need for quick-genned NPCs enough for me to actually compare the two, though, so I can't say for sure.