A few examples:
- Gem Dust.
A byproduct of cutting gems, it's currently a curios. Unfortunately it's a pretty bad curios, so not worth studying.
It has the potential to be used similarly to cave dust in some decent crafting. Maybe some jewels made with it? Or stained glass to make new symbels, gear, or even just colorful glass container?
- Golden Thread, Golden Cloth.
Only used for decoration, and recently for a pouch.
Golden Thread could be used to enhance a string-based crafting station (kind of like we use propolis and royal jelly on beehives)?
- Turpentine /wood polish.
Despite having 3 items made with it, wood polish (and Turpentine) are among the least crafted items. Most player don't bother making it, because the items are very niche. Given how many items are made with wood, wood polish could become a much more important item.
- Reindeer Antlers
Only used for the Reindeer cape, which is not good.
- Lots of hides.
While I don't think ALL hides necessarily need a specific use (considering Hide itself is already useful), it would be nice to have specific uses for at least a few. In particular, I think all tamed animal hides should become useful (since right now they grow in quality too slowly to make them "good hides" and have no special use [horse being an exception, with a bad helmet]), as well as hides from animals that don't give anything else useful when killed (Aurochs / Mouflon / Otter / Caverat / Stoat / Wildhorse).
- Cave trees's wood.
From Mound to Trombone Chantrelles, the only tree found in caves that gives useful wood is the Towercap (required by minehole). Considering how long it takes to get to lower levels where the giant mushrooms trees are found, it would be nice to unlock some new recipes with their wood or spores.
- Ores.
Black ore and Bloodstone are required by mineholes. When it comes to crafting though, nothing requires ores (a specific one or generic ores).
This is kind of the same logic behind hides. Sure ores are useful once smelted or as stone
but I think it's a lost opportunity to ignore it as a crafting material. I would have added Hops to the list, but that's a bit of a different issue so I'll ignore it for now.
I'm sure there's more items I didn't think of, but you get the gist
