Game Mod: Like the previous game, NWN2 comes with a toolkit for building new modules and even entire campaigns. They run the gamut from lousy and cliched to really damn good (rivaling or surpassing the official releases in a few cases). A good source is NWvault.
Genre Savvy: Used and lampshaded in the same sequence if the player was Genre Savvy — just before the end, Garius will notice if the protagonist previously removed all gear from the characters who joined him, noting "Nice try, but ultimately futile" before giving them equipment.
This also happens if they're still carrying all of their original equipment by the game's end.
Amie, Bevil and Kipp, but most prominently various NPCs involved in escort quests.
Also, Shandra Jerro.
Hard-Coded Hostility: Can be either played straight or averted, due to the advanced faction building system available to module builders. A faction can be made hostile, indifferent or friendly toward any and all other factions, including the "player" faction, independently as required.
Heroes Want Redheads: The only romanceable female companion, the druidess Elanee, with auburn hair. In addition, two other early companions who aren't romanceable: the half-demon rogue, Neeshka, and the ginger sorceress, Qara. If the player starts the game with a redheaded close-combat character, it's possible to create a well balanced party of four redheads.
Grobnar: No one really knows how big the Wendersnaven are. They could be thousands of Khelgars high! Khelgar Ironfist: What did I say 'bout usin' me as a unit of measurement?! Grobnar: Er, right, several Neeshkas high.
Hostage for MacGuffin: The githyanki commanders do this using Shandra as the hostage, but only after Bishop tracks them back to their hideout and you hack your way through most of their troops. Then Zeeaire discovers that you've got another one of the Plot Coupons embedded in your chest and they abandon the attempt.
Averted somewhat, the Infinity+1 Sword pales in comparison to some player-made items in terms of damage and is useless to half the classes, although its special powers are somewhat useful so your mileage may vary.
It doesn't help that the weapon doesn't have a type, so even if you are playing a fighter type, none of those useful feats that you've picked up along the way will apply to it. Though I have found it useful when playing a mage.
Inn Security: Usually the Sunken Flagon is pretty safe, given that it's frequented by adventurers and off-duty guards. The exception is when the githyanki attack and take Shandra Hostage for a MacGuffin.
In the first area you visit outside of your Doomed Hometown — the road to some seemingly-unimportant swamp ruins — the minimap reads "The Mere of Dead Men". Now, the player character knows the apt name of the creepy swamp their home village is built on, but the player isn't supposed to know that yet. Also, one of the initially greyed-out prestige classes is Neverwinter Nine, potentially spoiling the offer Lord Nasher makes to you much later in the game.
Also, since the developers didn't bother/weren't able to make it possible to change the names of NPCs on-the-fly and weren't willing to outright lie to the player, you can tell that someone's going to try and deceive you about their identity if the overhead label that appears when you mouse over them says something vague, like "Man", instead of their actual name.
Similar to above, while walking through town, you can cursor over various NPCs. Citizen, Citizen, Citizen, Thug ... gee, I wonder which of these will try to ambush me as I walk past...
Mask of the Betrayer and certain fan modules prove that it is in fact possible to script a character name change (the MotB instance being Kaelyn the Dove adding a similar Animal Moniker to your name), so we can probably put this one down to Obsidian not caring enough.
Similarly, you are told to rescue an envoy but that his name is unknown... however his name shows up in your Journal straight away.
Johcris's anger makes more sense if you choose the conversation route that does not stop the fighting. If that occurs, you end up killing his daughter — which is a slightly bigger offense, no? Oh, and there is no way you can not kill his daughter if that happens. They sort of just start fighting you.
Also potentially Sand. Sure, Qara's not safe, and on her current path would no doubt turn out to be a major problem for anyone who crosses her. On the other hand, maybe that's a conversation we could have after we, y'know, defeat the Omnicidal Maniac before he rewrites reality.
The Silver Sword of Gith, an Ancestral Weapon of the githyanki and githzerai forged by Zerthimon for Gith to free them from the mind flayers. In the backstory it was lost in the Nine Hells, then recovered by Ammon Jerro to fight the King of Shadows, during which battle it was shattered. Its shards act as Plot Coupons to allow the blade to be reforged.
Limited Special Collector's Ultimate Edition: First there was the Special Edition, which added the aforementioned "Blessed of Waukeen" feat to the Knight-Captain. It gave access to a couple of special shops, as well as a minor bonus on some dice rolls. Then there was the Gold Edition, which bundled the Special Edition with Mask of the Betrayer. After Storm of Zehir came out, they added it to the Gold box and created the Platinum Edition; it is this version that is available on Steam.
Logic Bomb: Subverted in the final boss battle. The Knight-Captain can try to pull this on the King of Shadows by pointing out that its overarching purpose, protecting Illefarn, is no longer applicable since said realm no longer exists. The King has extended the definition of Illefarn to include its descendants.