PoloPoPo beat me to it.
In addition to that, I will say that there are some items that aren't included in any recipe, but might have other uses. A couple examples: old cash, which can either be scrapped to paper or sold to the trader, or fishing weights, also can be scrapped to lead or sold to the trader. There are others that have absolutely no use to you, cannot be scrapped, but are extremely valuable to a trader, like Silver and Gold nuggets.
Another tip if you don't already know it: an items sell value can be seen when the item is selected in your inventory in the top right corner of the window. The value is the total value of the stack (if there are multiple), not a single unit. The sell value is the same regardless of which trader you go to, though there are certain perks or consumables that can increase the value.
Last tip (just cause I'm thinking about it now): As you progress further, you'll likely find armor and weapons/tools that you either don't want to use, don't need for their parts, or are duplicates of what you already have. Depending on quality, the trader will buy them from you for a decent amount of Dukes. While you might be tempted to sell all of these items right away, it's smart to hold onto them until you have spare mods (which you'll also start a collection of) to put in them. Mods
greatly increase the value of items you sell to the trader, often getting you more money than just selling them all individually.