A few more;
Items;
A barrel of fire-quenching quarrels; each of these crossbow bolts has a canvas bag tied to its end. When fired above a torch or shot at a small campfire, these bolts release a spray of powder as the bag ruptures on impact. This whitish powder releases a cloud of heavy gas when it burns that immediately blankets the fire, cutting off the oxygen, thus extinguishing it. These are beloved by thieves and rogues everywhere as a way of "turning out the lights".
An obsidian box of yellow "dust" is in fact a batch of dried Toothworm eggs; this Underdark worm lays its tiny yellow eggs in fungi that are then eaten by animals. The eggs lodge in the intestine and await a chemical signal to hatch, persisting for decades. This chemical is naturally found in Underdark lakes and is released when the host drinks water containing a species of blind cave fish. At this point the eggs hatch, kill the land host, eating their way out in minutes, and enter the water to infect the cave fish. The cave fish gives rise to the second stage larvae that kill the fish and cause it to rise to the surface of the lake where fruiting bodies spread thousands of tiny spores into the air to disperse this organism thoughout the Underdark. These spores germinate on Underdark fungi to form the third stage larvae that eat their way in and lay eggs inside the fungus and so on.....
The Duergar now use/sell toothworm eggs as a special blackmail/assassination tool. They infect surface dwellers with the eggs and then reveal what they have done at sometime afterwards. They then threaten to dope the infected person's drinks or food with the Underdark lakewater at some future date unless the person does what they desire. They plan to bring even royalty to heel with this plan since no poison taster could detect the chemical trigger as it is harmless to uninfected people. Their victims will therefore live in constant terror and cannot not easily hide from their tormentors; the blackmailers could poison the wells of an entire city by placing cave fish in them and in nearby streams and lakes and only kill those people they had previously infected. This also ensures that the Duergar are able to kill their intended targets no-matter how well hidden they are, as everyone drinks sooner or later.
Box of glowrocks; these colourless glass-like gem facets are used in the Underdark to create heat when there is no fuel. If a small amount of water is poured on them, they create a vast amount of heat for several hours flame as the minerals react with the water. They are useful, if dangerous fire-lighters or they can be used to cook on without producing any smoke.
A barrel of black treacle-like material in fact contains something the Duergar trade with the Drow for; Spidertar. This tar like substance is extracted from certain spiders and can be poured into moulds where it will harden after several hours contact with air. The Drow use this to make weapons with when metal is in short supply. The Duergar sell it to thieves guilds who like swords made of spidertar as the blades are very light and extremely silent; no noise of blade on blade to give them away during ambushes. The spider-tar is also slightly absorbant and so applied poisons enter into the substance of the blades and persist for twice as long as normal.
A large crate contains bags of dark red powder called Dragon's bile. This is a secret substance, discovered by the Duergar, that allows them to smelt (extract from ore) titanium and aluminium. This is added to the ores before melting and whereupon it removes the oxide from the ore to yield free metal. Note that in the the real world, no chemical can reduce these ores and it is done using electricity; hence why Al and Ti were never present before the modern age even though their ores are very common.
A small 1 ft by 1 ft box contains a shiny metallic powder called Glowfire dust. When put on a fire, this powder heats the fire up by a factor of 4, increasing the temperature of the fire but consuming fuel much more quickly. This is a slow reaction and so is no use in combat. Glowfire is used for smelting various metals e.g. aluminium and titanium to make lightweight armour. The Duergar call these metals Nordite and Galenium. They sell Glowfire to those interested in smelting or alchemy.