Meanwhile in Arcana, two recent ideas were suggested to me:
1. Some way to make gunpowder using alchemy. Looking into it, I feel like the best way to do that would be a recipe for making a decent amount of gunpowder from non-standard materials, using the same basic set of components and tools used for the alchemy recipes to make silver and gold. So that means you need red potion plus the very basics of a metalworking setup. Since blackpowder is in comparison easy to make but uses materials that can be a pain in the ass to get ahold of (and are effectively loot-only), using a more advanced yet still accessible toolset plus something that's rare but craftable with effort seems like a good side method.
2. Grenade-type explosives keep coming up as a suggestion. The obvious idea that came to mind was elemental themed weapons making use of the talisman items you can learn to make. Key ideas that come to mind include optionally arming them on ranged impact, and elemental damage types in the BN version since fragmentation can be set to use exotic damage types in BN.
Did some testing as a part of once again trying to translate the weird old power stat of explosives into the damage method used in BN. DDA has...well, let's say the kinda shit I run into every time I test DDA for longer than a minute: