A few ideas from me (Don't know if they've ben suggested)
As stated, I don't know if these have been posted. Still, give me your input/criticisim.
Poison (botany, poisonous berries), can be applied to slashing/piercing weapons, but only work for one attack. Good for hunting game if you can get a hold of some arrows or throwable spears, but the effects take too long to take to be useful in a combat situation (Unless you want to ensure the guy dies at some point).
Rat Trap (Trapping, sharp edge, medium rigid springy shafts, small parts) are traps that can be used in urban areas. They can trap rats, that will yield small meat and a pelt.
Punji Trap (trapping, sharp edge, medium rigid springy shafts, tarp)(can have poison applied), if put on the ground or in your campsite, can damage unaware opponents if they enter your hex and cause them to skip a turn. They may accidentally come across it without falling into it. It doesn't increase any of the stats and takes up room, but if you want to lure scavengers and ambush them, make game easier to kill, or simply protect yourself it might be a good investment.
Battery Lighter (electronics, energy source, small parts), can be used to start fires and torches, but cannot be used as a light source. Good if you have no lighters available to you.
Tarp Poncho (sharp edge, poncho, small threads), is a coat that covers the torso and negates the effects of rain.
Search for game (Tracking) lets you know if there is any small animals in the area. Also includes the likelihood of you getting a small animal without a trap, though traps will still help.
Scavenge for parts (electronics) increases the likelihood of finding useful crafting components, but can only be done in urban environments.
Check for Power (electronics) can only be done in urban environments, and checks the building you are scavenging has power available. If it is, you can choose to...
Turn on power (electronics), which allows for lighting and the crafting of electric charges, provided you have the right parts. It lights the hex you are on, as well as one hex away to a lesser degree.
Check for heating (mechanical), which can only be done in urban environments, allows you to check the building's HVAC system. And, as you guessed...
Turn on heating (mechanical), which heats the building. It's a more stealthy approach to heating, but it still reduces stealth a little bit.
Check Campsite (No related skill, but can be enhanced with eagle eye, trapping/botany if outdoors, or mechanical/electrical if urban) Gives you a general (but sometimes inaccurate without proper skills) stat range for camp elements you don't have the skills to find (Concealment if you don't have hiding, healing if you don't have medic, alertness if you don't have trapping). It also doesn't show how much your camp will be affected by changes like fires or traps.
Skills & Traits:
Barter allows for better prices when buying or selling items. Can also be used to offer trade to non-hostile NPCs.
Intimidation increases the succesor instans of intimidation checks,(Like wearing the Dog Man cloak), and opens several alternative doors (intimidate guards at Zom Zoms to let you go, fce) makes you appear more intimidating
Charisma makes non-hostile NPC's more friendly to you (DMC guards won't leave after you ask them what they think is a stupid question), and offers alternative solutions to problems (Desk clerk at Zom Zom's will explain the difference between stock and spectator, and might let you in for free)
Cowardly reduces your effectiveness in any form of combat, but makes you slightly better at running away or hiding.
Unfit increases fatigue when moving and decreases moves per turn. Cannot take Athletic
Clumsy makes you more prone to tripping.
Infirm starts you with a random mild injury or sickness.
Uncouth reduces your effectiveness in social situations, and might make non-hostile NPCs avoid you. Cannot take charisma or Barter, and negates your intimidating presence perk in the Intimidation skill (But still gives you your intimidation options and successes)
Borrowed Time opens two (or more) skill slots, but sets a time limit to when you have to complete the game, or else you die.
Guards are generic guards outside the DMC and ATN. They will be non-hostile unless threatened. They will often be decently armed and dressed to fight, and are tough and strong. If you have the money or something to trade, you could offer to hire their services for a few days, but might take some loot for themselves on occasion.
Merchants can be spoken to, even if you have Uncouth (Though they will seem wary of you). They will often be accompanied by a guard or two (DMC or ATN if close enough to their territory, otherwise they have a guard that follows them), and will sometimes have a looter to help look for anything on the way (Acts like normal looters). They will trade with you, which will open up their campsite as a trading ground (place items in it to sell, take items to buy). If you are uncouth, the prices will definitely not be in your favor.
New Day Cultists is another cult that believes the end was simply a new dawn, that the Dark Ages of ancient times is being repeated to weed the weak from the strong. They are non-hostile, and the leaders are not (openly) against Uncouth players. They will offer literature and a chance to follow them on their journey to spread the word. Leaders are pacifists, but followers carry weapons to protect their leaders. Members wear bright orange beanies that hinder hiding abilities, but offer a decent bonus to warmth. They also tend to travel in groups of three to five with at least one leader.
Bandits (I know they were in the game already, but they should be back in) are hostile NPCs that are not associated with the Bad Muthas or Blue Frogs. They might not be as well equipped as either group, but are not likely to attack you if you're Intimidating, and might even become non-hostile or talkative if you have Charisma (Though their dialogue is them sarcastically warning you against "all of those bad guys" out there). Even so, they sometimes come in groups of up to three, and then will only back off if in a losing fight or successfully intimidated.
Citizens are non-hostile NPCs. Instead of just "Citizen", though, they have job titles like Hunter/Gatherer, Scavenger, Forrester, ect.
Tradesmen are like guards, except they offer personal services instead of protection. Tradesmen would be medics (Heal you), hackers (unlock electronics), botanists(identify plants, craft with them), locksmiths (open locked containers), trappers (make traps, shelters, and prepare animals), electricians (craft electronic devices, check for/bring power to your camp), and mechanics (Mechanical crafting, check for/bring heating to your camp). They can hold their own in a fight, but will flee if the fight goes south.
Black Bears are hostile if you are within a certain distance (We'll say 20 or less for the sake of discussion), but if you have Trapping, Tracking, or intimidation, you can get closer (we'll say 10) even if it sees you so long as you approach slowly.
Wolf Hounds are hostile, come in packs of up to five, and are fast, but much easier to kill than Dog Men. If you kill the Alpha, it's likely the pack will flee combat.
Cockatrices are the winged creatures you see in your first ruins. They are weak and easy to kill, but have a poisonous but non-fatal bite that increases fatigue until you black out.
Dire Rats are more common in ruins than any other urban area. They can get up to six in a pack, are easy to kill, and are non-aggressive if there are three or less rats (five or less if you're Intimidating), but their bites are more likely to get infected.
Mutants are stronger, faster, and aggressive than your average human. They don't call for backup, but are dangerous in combat. The only advantage you have is that they do not think defensively or stealthily, but if you are facing more than one (Up to three at a time), your best option is to run away and/or hide. If killed, they drop their weapons (usually large tree branches), dirty rags (since their clothes tend to be worn and shredded) and sometimes drop food.
More to come, maybe.