I have posted something akin to this before, but that was a while ago and I would like to discuss this further.

I feel that magical materials as they are in D&D could use a little more expansion. I like mythral and adamantium, but I would really like to look into some more materials that could be added. 

I like that silvered weapons are effective against certain creatures such as werewolves, so maybe other real life metals could have effects?

• I know that a thin sheet of lead blocks magic items such as the Ring of X-Ray Vision, so maybe it could give you some kind of benefit against psychic damage if your armor is coated in it.
• Copper is very conductive, so maybe if you are hit with an attack that deals lightning damage, you can, as a reaction, hit a creature with a copper weapon to channel a fraction of the damage into them?
• Meteoric iron is already pretty exotic, so it would be easy to give it some sort of unique effect.

What about materials from monsters? 

• Troll blood is pretty sought after for its usefulness for healing potions, but trolls are prone to mutation. What if you could drink trolls blood to heal oneself, but there's a chance of it mutating you. Drinking it to heal a broken bone could cause the bone to heal wrong, disfiguring you. Drinking it to cure petrification could leave your skin dry and cracked like weathered stone.
• Armor crafted from dragons could grant you immunities to damage from that dragons specific breath weapon. 

If you have any ideas to add, whether that be things you have come up with or seen in D&D books, feel free to place them below this post!

If you want to copy IRL, you could have weapons made from: Damascus Steel, Bronze, Steel, Iron, Flint, Obsidian (volcanic glass), diamond-edging.

• Armor crafted from dragons could grant you immunities to damage from that dragons specific breath weapon. 

This already exists: Dragon Scale Armor is in the DMG.

Technically speaking adamantine and mithral (“i” not “y”) are not “magical materials” this edition like they used to be in older editions. There apparently are no innately magical materials in 5e.

Quote from IamSposta >>

Technically speaking adamantine and mithral (“i” not “y”) are not “magical materials” this edition like they used to be in older editions. There apparently are no innately magical materials in 5e.

 I see you everywhere dude, you're like the D&D beyond MVP

Subbed to your channel BTW

Thanks, lol. I appreciate that. And thank you for subbing too! I don’t post much on YouTube, so I hope you aren’t disappointed.