VTC - Brainstorming questions aren't appropriate for this site.

I agree with @TheDemonLord. Questions asking for lists of random items are regularly closed. You're asking for an off-topic infinite list of things, even with the explodable condition. You're also not asking a worldbuilding question. Worldbuilding rules/conditions/constructs are always true regadless any story built around them. You're asking for a list of props for your story. However, this would be a perfect question to ask in the storytellers corner chat room.

@JBH I really don't understand why "what chemicals are industrially useful and shock-sensitive" is close-worthy, but "what crops are efficient for industrial farming with limited land" isn't? They seem like very close mirrors of each other. "here are some constraints, do any real-world things fit these conditions?"

@Kaia You've asked a good question. It boils down to this: questions asking for a finite list of things have been declared on-topic by the community, questions asking for an infinite list of things (i.e., a very long list) have been declared off-topic by the community. Agriculture given a restricted condition list genreally results in 2-8 options. There are thousands of unstable liquids and solids that could be put in a barrel. ... (Continued)

... But it's also worth noting that edible food is a worldbuilding issue. One cannot have a society of any kind without agriculture. This is a request for story props as no society needs this to exist.

This is an interesting question --- or rather it would be if it were written differently! I concur with DemonLord and JBH that you're just asking for a list of explosive things. Story props. However! JBH gave you, perhaps inadvertently, a hint as to how to bring this question back on topic and can potentially make it a banger of a worldbuilding query! Notice the throwaway tag line: no society needs this to exist. Given that your focus is on materials, on props for your setting, he's 100% correct. Society doesn't need these things. I'm challenging you, therefore, to turn (cont)

(cont) your query around on its head and make this a question about rules of the world. You kind of hint at it yourself, that game tropes are justified. They're part of the world. Therefore, focus your question on this rule of the world! Make this a question about a society that needs red barrels of explosivity in order to exist!

I happen to disagree with everyone; this is not an infinite list question and is perfectly on-topic. (The only reason I'm not voting to reopen is I'm personally iffy on the wisdom of being too helpful with questions which could be easily used for real world harm, and "common explosive industrial chemicals"...)

By coincidence, the other day I was playing Half-Life 2 to listen to the commentary track, and one of the developers admitted (regarding the plausibility of a room chock full of exploding barrels) that when it comes to plausibility, one exploding barrel is already over the line. "Barrels aren't supposed to explode, even when you shoot at them."

Propane tanks solve this problem, imho.

@Jedediah Trust me, we've answered so many questions about poisons, explosives, and weapons of mass destruction that you were likely added to the U.S. Homeland Security watch list just for joining the stack. On the other hand, there really is a difference between storybuilding and worldbuilding and storybuilding belongs in chat, not on Main.

@DanielB I'm afraid that's Hollywood. Propane tanks are almost impossible to set off with a bullet. They're not hot enough and they move so quickly they don't cause a big enough spark. There's a lot of videos out there demonstrating this. Propane tanks are remarkably safe... but I wouldn't let that stop a video game. (Now, after the gas has been released, a bullet still won't do it but propane expands at 10,000:1 so a 20# propane tanks releases ~42,000 gallons of propane gas. That's why blocks are leveled when there is a propane explosion.)

Huh. I could have sworn I saw a youtube video of someone blowing up propane tanks with a shotgun. I wonder what was in them?

@JBH I got pretty cynical about other people's ability to judge between personally interesting vs off-topic when a question about whether a spaceship could have basic equipment to mine titanium (to repair its damaged hull) on an earth-like planet. I wasn't particularly interested, but it seemed on-topic. It was closed.

Its really just ammonitions production, because that is where those barrels are the final product. Everywhere else- any sane society who wants to continue production dissolves anything dangerous as fast as possible

@Jedediah the whole close a topic process is flawed. A question should traverse a factoria like intake and process stages, were it can be rewritten (if the author is lazy) or even reformulated. But never closed. Closing encourages lazy bitching.

@JBH There is some difference between "This super-unstable compound which you'd probably die trying to produce at scale is..." and "A barrel of this common and accessible industrial chemical is basically already a bomb if you have a gun."

If a question does not life up to a tag- it gets tag challenged for a day, means the author can refine it- or it will be redirected, from hard scifi, to soft scifi, to fairy tales, to brainstorming

@JBH The infinite list/finite list distinction seeems silly--it depends on how you slice it. there's 100+ cultivars of soybean, so saying "2-8 options" is just taking a preference on binning? As for storybuilding: isn't this exactly the definition of "A good storybuilding question is an objective request for help resolving a story development problem..."