Loop Hero

Many of the resources don't drop until chapter 2+ with higher chances of dropping in the later chapters, so don't worry about this until you're pretty far in the game or beaten it. There's a good chance you'll get it naturally.

If you didn't, here is a great reference guide with what enemies/structures/cards drop each resource. I recommend visiting the website so you can click on the links if you need additional details about any interactions or cards, but I screenshotted it below in case the website ever dies.

https://loophero.fandom.com/wiki/Materials

A couple things to know:

• I did NOT need the last item on the list, Hydrogen. In fact, as of this writing, I still haven't built the Alchemist's Tent (which is required to obtain Hydrogen).
• The resource bundles that you can choose after beating a boss (instead of a perk) are a good place to get rarer materials. I got this achievement accidentally when I chose a resource bundle as my reward.
• You can check which resources you have in the Encyclopedia (unlocked after you build the Intel Center at the camp), so you can compare it to the reference guide and see what you're missing.