Fantasy Materials

[D&D_Fan]

There are a lot of fantastical materials in games like D&D and other fiction. Adamantium and Mithral, Telstang, Bone Steel, and the classic Unobtanium, to name a few. I am looking for suggestions for more materials that I and other DMs can use in campaigns. I play in 5e, but other systems are allowed. You can even make concepts without numbers.

I'll start with one taht can be adapted into any setting
Subteranium
A mystical metal that is seemingly the opposite to Starmetal/Meteor Iron. It is physically brittle, but deals an extra damage dice to living creature that aren't constructed or undead. Armor made of has a higher armor value/class when hit with Starmetal. It also has disadvantage against targets with Starmetal armor. It is unknown to must surface dwelling folk, and the specific crafting instructions are known only to a few drow, dwarven, and duergar smiths.

[John Out West]

I'm workin on something related, a book on crafting. I'll post an excerpt from the page on using special materials. Maybe something in there will help/inspire. (This is tuned for D&D 5e)

Dour Wood
Alchemical Iron
Swamp Feed
Alicorn
Passion Cairns
Lunarite

And my own take on Mithril, Adamantine, and Dragon Bone.

[Sam113097]

I like this! Right now, I have a couple in the setting I run a game in:

Azure Steel: Forged in the fires of the Ever-lasting Flame, a gift given to mortals by a god to defend themselves from rogue demigods. The blue-tinted metal that results from the process resists magic, making it excellent for armor or for Mage-Armor-and Shield-piercing arrows.

Giant Bone: The bones of the first giants are supernaturally hard, and hum with the magic of the earth god that created them. Weapons made of giant bone are supernaturally durable and inherently magical, though they are incredibly difficult to shape.

[D&D_Fan]

I'm workin on something related, a book on crafting. I'll post an excerpt from the page on using special materials. Maybe something in there will help/inspire. (This is tuned for D&D 5e)

This is really cool! If you want you can use Subterranium, but I know that name is awful so I'm using this post to rename it.

New name!
Official: Coremetal (as opposed to starmetal.)
Original/Tribal: Muitnamada (just adamantium backwards.)
Common: White Iron (it appears shiny white with orange shine.)

Now for a new thing!

True Ice
Extraordinary water from magic/extradimensional springs, or magic/extradimensional glaciers/icebergs. It cannot melt through normal means. It will only melt when exposed to magical flame (magic forges, continual flame, the plane of fire) for 7 days. It deals some extra cold damage on a hit, and is inherently magical. If it's magic is dispelled through dead/antimagic areas, as well as mordenkainen's disjunction and similar spells with permanent effects., it can melt like normal ice.

feedback is appreciated!

[Coins]

Celesteel-Ore mined from the celestial planes any weapon forged with this material gains the "holy" enhancement. Any armor or shield allows the wearer to cast protection from evil once a day.
Darksteel- Mined only from the blackest pits of the abyss. Weapons grant additional damage to lawful aligned creatures of 1d6 points of damage. Armors grant an additional 5 poison and electricity resistance.
Magmite or “Devil Iron”- Metal forged in hellfire from the nine planes of hell. Armors grant an additional fire and poison resistance of 5. Weapons grant an additional 1d6 points of damage to chaotic creatures.

[Bohandas]

Consekrete (Consecrated Pykrete)- An arctic shipbuilding and construction material made from holy water soaked pages of scripture that have been frozen solid. Among other properties, it prevents passage by evil incorporeal beings, and affects fiends and the undead as if it was holy water.

Venerium- The rigidity of this metal varies according to the user's mental state. Sometimes it is as hard as steel, and at other times it can be easily folded by hand

Neuromesh- A psionically reactive material made from woven nerve fibers

Homeopathic Water- Seawater that has been processed by removing both the water and the salt by measures, leaving behind a semi-tangable idea of water that can be swam in while still coexisting in the same location as breathable air

Incandescium- A metal which naturally gives off light passively

Prionic[sic] Water- Water which remains liquid well below the normal freezing temperature and causes any ice it comes into contact with to turn into more prionic water. Can be tjrned back into normal water by bringing it to its own much lower freezing temperature, or by boiling it.

Durajuana- A strain of hemp plant that can be woven into a fabric as strong as kevlar. It is also an entheogen and can be burned by a divine spellcaster during casting to provide a +1 alchemical bonus to the caster level of a divination spell.

Maanzicorium- Psionically active material mined from the astral fprm of the dead illithid deity Maanzicorian

Mega Hides/Shells/Bones/etc- Structural bodyparts harvested from gigantic creatures are necessarily significantly more durable than the same bodyparts harvested from regular creatures due to the fact that they need to support significantly more weight (cf. https://en.wikipedia.org/wiki/Square_cube_law)

Grave Bricks- Bricks made from grave dirt lend themselves to intensifying fear effects and Hallow and Unhallow effects (also Consecrate and Desecrate) inside of structures constructed of such bricks.

[Temotei]

I remember arguskos made some materials a long while ago. Don't think he ever finished, though. Here.

[Zhorn]

For the Critical Role fans out there
Residuum: "a green, glass-like substance. Although not inherently magical, it is particularly receptive to arcane energies and therefore may be used to create objects that retain more powerful enchantments, perhaps for longer periods of time. It can also be utilized to replace and act as other expensive materials and components for spells and other uses."
NOTE: I find this flavour of substance makes for a good treasure drop for when you have a player interested in making something and want to give them a short-cut without making ALL crafting too fast.

Final Fantasy players should be familiar with some versions of
Magicite: Magic stone, often left behind as the remains of a dead magical being (replace with your flavour of living god, ascended being, magic borne entity, etc)
Nethicite: Anti-magic material, can serve as either a disruption tool, stabilising agent, or magical storing substance
NOTE: I like to treat the above as families of materials rather than singular substances (eg: "this gem seems to exhibit nethicite properties"), emphasises that they are the result of something happening rather than being a naturally occurring substance.

Warhammer fans run on
Warpstone: Chaos given material form. Highly unstable, often results in rolls on the Wild Magic table if not handled carefully. A very unclean and corrupting material.

[Magicspook]

I recall reading some forgotten realms books about netheril. In the books, Karsus had invented a material he called 'heavy magic'. It was a kind of liquefied magic that took on the properties of whatever magic/material it touched (it was a little random). Possible applications were exploding ballista bolts and slime which enveloped people, holding them in place.

EDIT: don't forget about good old cold iron: this metal is the bane of elves and faeries, harming them like holy water harms undead and fiends. You can think of your own method of how it is made.

EDIT2: percy jackson has celestial bronze, a material so high that mortals cannot be harmed with it (it passes right through them), but demigods and monsters can.

[Breccia]

I'm pretty sure at least 75% of fantasy settings have some kind of "iron wood".

[Morphic tide]

Necrium: Typically formed from the remains of those deceased from prolonged paraelemental salt poisoning, Necrium is desiccated bodily tissues infused with extreme degrees of negative energy and elemental earth, hardening it to a considerable degree, so much so that hide and sinew compares to the durability of steel and bone approaches the strength of adamantine. However, it also consumes life essence on contact and drys living flesh, causing fatigue as if rest never comes unless magical healing is used to bolster the user and greatly raising need of water of users. Otherwise noteworthy bodily substances are exponentially more rare, with many dying in the search of rumors of Necrium Dragonhide, but any such substance can be created if one is so heartless as to commit to the prolonged torturous demise of the creature to be harvested.

Soulsilt: Generally found in the riverbeds of excessively frequently haunted docks, Soulsilt is an exceedingly heavy sediment formed from Astral rifts allowing clay to fold over itself, with the ossified connection causing it to quickly become bone-dry and shatter into fine grains unless soaked in both the Astral plane and the Prime Material or exposed to exceptionally infused water, generally blessed by Divine magic, though some societies insist on the use of elementally exemplary water. Typically used to create exceptionally hard mortar and brick impermeable to Astral intruders, the use of paraelemental ooze for hydration can cause it to form a peculiarly hardy gel, suitable for many similar purposes to hide or rope but easily mended by simple pressure and endlessly reformed into different items, albeit of much greater weight than conventional materials.

[Bohandas]

Annum Wax Wax harvested from used birthday candles is useful in time magic. Both for enhancing it, and for warding against it by coating the creature or object to be protected with the wax

Shard Glass/Shard Metal Unlucky materials made out of broken mirrors that have been melted down. Used in the creation of cursed items

Ostagre Concrete- Lower planar concrete using crushed and broken bones as it's aggregate material.

Conflasicum- A breed of chili pepper grown on the elemental plane of fire whose flesh is useful in fire magic

Ostentatium- Material formed by melting down silver, gold, and platinum, mixing in an aggregate of mixed gemstones, and then letting the metals run together but not completely mix. It is used in items sanctified to deities, particularly chaotic deities, particularly deities of bards and rogues.

Treant Wood/Paper- made from treants

Flesh Diamond Diamonds occasionally formed by the use of the Implosion spell

Lunar Regolith Fine abrasive soul from the surface of the moon. Throwing it onto a lycanthrope will cause them to change.

Moon Rocks Rocks from the moon. A structure incorporating a large number of them, arranged correctly, will force entering lycanthropes to change forms.

Room Temperature Superconductors Zero electrical resistance without having to be frozen

Magnetic Monopoles magnetic particles that are all north with no south or all south with no north