Here is my first small list of NPCs for you
6:1 Geckos, Pigrats, Radtoads
7:1 Trappers
7:2 Dogs, Molerats, Pigrats, Farmers, Golden Geckos, Scorpions, Bandits, Homeless
7:3 Farmers, Lone Wanderer, Geckos, Silver Geckos, Golden Geckos, Pigrats, Molerats
7:4 Geckos, Trappers, Lone wanderer
8:1 Geckos, Pigrats, Scorpions, Radscorpions, Molerats
8:2 KLAMATH
8:3 Pigrats, Molerats, Radscorpions, Caravan
9:2 Pigrats, Molerats, Radscorpions
9:3 Caravan
13:9 Raiders, Ants
14:10 Homesteaders, Trappers, Claim jumper
17:14 Geckos, Molerats
17:27 Centaurs, Geckos
24:19 Giant rats, Radscorpions
27:8 Vault City patrol
29:13 Raiders, Broken Hills caravan
29:14 Broken Hills caravan
29:16 Pigrats, Molerats
29:23 Molerats
29:35 New Reno caravan
29:36 Molerats, Radscorpions, Junktown scouts
29:37 Pigrats
30:24 Molerats
30:35 New Reno caravan, Raiders, Junktown scouts
31:36 JUNKTOWN
31:37 Radscorpions, Junktown scouts
32:23 NCR caravan
32:26 Brahmins
32:36 Small radscorpions, Scorpions, Junktown scouts
33:31 NCR Caravan, Small radscorpions